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ARM: rockchip: fix broken build
[linux/fpc-iii.git] / fs / btrfs / free-space-cache.c
blobfb5a6b1c62a65684b73ab7b0f6a2f2d918615935
1 /*
2 * Copyright (C) 2008 Red Hat. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/pagemap.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/math64.h>
23 #include <linux/ratelimit.h>
24 #include "ctree.h"
25 #include "free-space-cache.h"
26 #include "transaction.h"
27 #include "disk-io.h"
28 #include "extent_io.h"
29 #include "inode-map.h"
30 #include "volumes.h"
31
32 #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8)
33 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
34
35 struct btrfs_trim_range {
36 u64 start;
37 u64 bytes;
38 struct list_head list;
39 };
40
41 static int link_free_space(struct btrfs_free_space_ctl *ctl,
42 struct btrfs_free_space *info);
43 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
44 struct btrfs_free_space *info);
45
46 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
47 struct btrfs_path *path,
48 u64 offset)
49 {
50 struct btrfs_key key;
51 struct btrfs_key location;
52 struct btrfs_disk_key disk_key;
53 struct btrfs_free_space_header *header;
54 struct extent_buffer *leaf;
55 struct inode *inode = NULL;
56 int ret;
57
58 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
59 key.offset = offset;
60 key.type = 0;
61
62 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
63 if (ret < 0)
64 return ERR_PTR(ret);
65 if (ret > 0) {
66 btrfs_release_path(path);
67 return ERR_PTR(-ENOENT);
68 }
69
70 leaf = path->nodes[0];
71 header = btrfs_item_ptr(leaf, path->slots[0],
72 struct btrfs_free_space_header);
73 btrfs_free_space_key(leaf, header, &disk_key);
74 btrfs_disk_key_to_cpu(&location, &disk_key);
75 btrfs_release_path(path);
76
77 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
78 if (!inode)
79 return ERR_PTR(-ENOENT);
80 if (IS_ERR(inode))
81 return inode;
82 if (is_bad_inode(inode)) {
83 iput(inode);
84 return ERR_PTR(-ENOENT);
85 }
86
87 mapping_set_gfp_mask(inode->i_mapping,
88 mapping_gfp_mask(inode->i_mapping) &
89 ~(__GFP_FS | __GFP_HIGHMEM));
90
91 return inode;
92 }
93
94 struct inode *lookup_free_space_inode(struct btrfs_root *root,
95 struct btrfs_block_group_cache
96 *block_group, struct btrfs_path *path)
97 {
98 struct inode *inode = NULL;
99 u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
100
101 spin_lock(&block_group->lock);
102 if (block_group->inode)
103 inode = igrab(block_group->inode);
104 spin_unlock(&block_group->lock);
105 if (inode)
106 return inode;
107
108 inode = __lookup_free_space_inode(root, path,
109 block_group->key.objectid);
110 if (IS_ERR(inode))
111 return inode;
112
113 spin_lock(&block_group->lock);
114 if (!((BTRFS_I(inode)->flags & flags) == flags)) {
115 btrfs_info(root->fs_info,
116 "Old style space inode found, converting.");
117 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
118 BTRFS_INODE_NODATACOW;
119 block_group->disk_cache_state = BTRFS_DC_CLEAR;
120 }
121
122 if (!block_group->iref) {
123 block_group->inode = igrab(inode);
124 block_group->iref = 1;
125 }
126 spin_unlock(&block_group->lock);
127
128 return inode;
129 }
130
131 static int __create_free_space_inode(struct btrfs_root *root,
132 struct btrfs_trans_handle *trans,
133 struct btrfs_path *path,
134 u64 ino, u64 offset)
135 {
136 struct btrfs_key key;
137 struct btrfs_disk_key disk_key;
138 struct btrfs_free_space_header *header;
139 struct btrfs_inode_item *inode_item;
140 struct extent_buffer *leaf;
141 u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
142 int ret;
143
144 ret = btrfs_insert_empty_inode(trans, root, path, ino);
145 if (ret)
146 return ret;
147
148 /* We inline crc's for the free disk space cache */
149 if (ino != BTRFS_FREE_INO_OBJECTID)
150 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
151
152 leaf = path->nodes[0];
153 inode_item = btrfs_item_ptr(leaf, path->slots[0],
154 struct btrfs_inode_item);
155 btrfs_item_key(leaf, &disk_key, path->slots[0]);
156 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
157 sizeof(*inode_item));
158 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
159 btrfs_set_inode_size(leaf, inode_item, 0);
160 btrfs_set_inode_nbytes(leaf, inode_item, 0);
161 btrfs_set_inode_uid(leaf, inode_item, 0);
162 btrfs_set_inode_gid(leaf, inode_item, 0);
163 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
164 btrfs_set_inode_flags(leaf, inode_item, flags);
165 btrfs_set_inode_nlink(leaf, inode_item, 1);
166 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
167 btrfs_set_inode_block_group(leaf, inode_item, offset);
168 btrfs_mark_buffer_dirty(leaf);
169 btrfs_release_path(path);
170
171 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
172 key.offset = offset;
173 key.type = 0;
174 ret = btrfs_insert_empty_item(trans, root, path, &key,
175 sizeof(struct btrfs_free_space_header));
176 if (ret < 0) {
177 btrfs_release_path(path);
178 return ret;
179 }
180
181 leaf = path->nodes[0];
182 header = btrfs_item_ptr(leaf, path->slots[0],
183 struct btrfs_free_space_header);
184 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
185 btrfs_set_free_space_key(leaf, header, &disk_key);
186 btrfs_mark_buffer_dirty(leaf);
187 btrfs_release_path(path);
188
189 return 0;
190 }
191
192 int create_free_space_inode(struct btrfs_root *root,
193 struct btrfs_trans_handle *trans,
194 struct btrfs_block_group_cache *block_group,
195 struct btrfs_path *path)
196 {
197 int ret;
198 u64 ino;
199
200 ret = btrfs_find_free_objectid(root, &ino);
201 if (ret < 0)
202 return ret;
203
204 return __create_free_space_inode(root, trans, path, ino,
205 block_group->key.objectid);
206 }
207
208 int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
209 struct btrfs_block_rsv *rsv)
210 {
211 u64 needed_bytes;
212 int ret;
213
214 /* 1 for slack space, 1 for updating the inode */
215 needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
216 btrfs_calc_trans_metadata_size(root, 1);
217
218 spin_lock(&rsv->lock);
219 if (rsv->reserved < needed_bytes)
220 ret = -ENOSPC;
221 else
222 ret = 0;
223 spin_unlock(&rsv->lock);
224 return ret;
225 }
226
227 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
228 struct btrfs_trans_handle *trans,
229 struct btrfs_block_group_cache *block_group,
230 struct inode *inode)
231 {
232 int ret = 0;
233 struct btrfs_path *path = btrfs_alloc_path();
234 bool locked = false;
235
236 if (!path) {
237 ret = -ENOMEM;
238 goto fail;
239 }
240
241 if (block_group) {
242 locked = true;
243 mutex_lock(&trans->transaction->cache_write_mutex);
244 if (!list_empty(&block_group->io_list)) {
245 list_del_init(&block_group->io_list);
246
247 btrfs_wait_cache_io(root, trans, block_group,
248 &block_group->io_ctl, path,
249 block_group->key.objectid);
250 btrfs_put_block_group(block_group);
251 }
252
253 /*
254 * now that we've truncated the cache away, its no longer
255 * setup or written
256 */
257 spin_lock(&block_group->lock);
258 block_group->disk_cache_state = BTRFS_DC_CLEAR;
259 spin_unlock(&block_group->lock);
260 }
261 btrfs_free_path(path);
262
263 btrfs_i_size_write(inode, 0);
264 truncate_pagecache(inode, 0);
265
266 /*
267 * We don't need an orphan item because truncating the free space cache
268 * will never be split across transactions.
269 * We don't need to check for -EAGAIN because we're a free space
270 * cache inode
271 */
272 ret = btrfs_truncate_inode_items(trans, root, inode,
273 0, BTRFS_EXTENT_DATA_KEY);
274 if (ret)
275 goto fail;
276
277 ret = btrfs_update_inode(trans, root, inode);
278
279 fail:
280 if (locked)
281 mutex_unlock(&trans->transaction->cache_write_mutex);
282 if (ret)
283 btrfs_abort_transaction(trans, root, ret);
284
285 return ret;
286 }
287
288 static int readahead_cache(struct inode *inode)
289 {
290 struct file_ra_state *ra;
291 unsigned long last_index;
292
293 ra = kzalloc(sizeof(*ra), GFP_NOFS);
294 if (!ra)
295 return -ENOMEM;
296
297 file_ra_state_init(ra, inode->i_mapping);
298 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
299
300 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
301
302 kfree(ra);
303
304 return 0;
305 }
306
307 static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
308 struct btrfs_root *root, int write)
309 {
310 int num_pages;
311 int check_crcs = 0;
312
313 num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
314
315 if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
316 check_crcs = 1;
317
318 /* Make sure we can fit our crcs into the first page */
319 if (write && check_crcs &&
320 (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
321 return -ENOSPC;
322
323 memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
324
325 io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
326 if (!io_ctl->pages)
327 return -ENOMEM;
328
329 io_ctl->num_pages = num_pages;
330 io_ctl->root = root;
331 io_ctl->check_crcs = check_crcs;
332 io_ctl->inode = inode;
333
334 return 0;
335 }
336
337 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
338 {
339 kfree(io_ctl->pages);
340 io_ctl->pages = NULL;
341 }
342
343 static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
344 {
345 if (io_ctl->cur) {
346 io_ctl->cur = NULL;
347 io_ctl->orig = NULL;
348 }
349 }
350
351 static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
352 {
353 ASSERT(io_ctl->index < io_ctl->num_pages);
354 io_ctl->page = io_ctl->pages[io_ctl->index++];
355 io_ctl->cur = page_address(io_ctl->page);
356 io_ctl->orig = io_ctl->cur;
357 io_ctl->size = PAGE_CACHE_SIZE;
358 if (clear)
359 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
360 }
361
362 static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
363 {
364 int i;
365
366 io_ctl_unmap_page(io_ctl);
367
368 for (i = 0; i < io_ctl->num_pages; i++) {
369 if (io_ctl->pages[i]) {
370 ClearPageChecked(io_ctl->pages[i]);
371 unlock_page(io_ctl->pages[i]);
372 page_cache_release(io_ctl->pages[i]);
373 }
374 }
375 }
376
377 static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, struct inode *inode,
378 int uptodate)
379 {
380 struct page *page;
381 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
382 int i;
383
384 for (i = 0; i < io_ctl->num_pages; i++) {
385 page = find_or_create_page(inode->i_mapping, i, mask);
386 if (!page) {
387 io_ctl_drop_pages(io_ctl);
388 return -ENOMEM;
389 }
390 io_ctl->pages[i] = page;
391 if (uptodate && !PageUptodate(page)) {
392 btrfs_readpage(NULL, page);
393 lock_page(page);
394 if (!PageUptodate(page)) {
395 btrfs_err(BTRFS_I(inode)->root->fs_info,
396 "error reading free space cache");
397 io_ctl_drop_pages(io_ctl);
398 return -EIO;
399 }
400 }
401 }
402
403 for (i = 0; i < io_ctl->num_pages; i++) {
404 clear_page_dirty_for_io(io_ctl->pages[i]);
405 set_page_extent_mapped(io_ctl->pages[i]);
406 }
407
408 return 0;
409 }
410
411 static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
412 {
413 __le64 *val;
414
415 io_ctl_map_page(io_ctl, 1);
416
417 /*
418 * Skip the csum areas. If we don't check crcs then we just have a
419 * 64bit chunk at the front of the first page.
420 */
421 if (io_ctl->check_crcs) {
422 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
423 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
424 } else {
425 io_ctl->cur += sizeof(u64);
426 io_ctl->size -= sizeof(u64) * 2;
427 }
428
429 val = io_ctl->cur;
430 *val = cpu_to_le64(generation);
431 io_ctl->cur += sizeof(u64);
432 }
433
434 static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
435 {
436 __le64 *gen;
437
438 /*
439 * Skip the crc area. If we don't check crcs then we just have a 64bit
440 * chunk at the front of the first page.
441 */
442 if (io_ctl->check_crcs) {
443 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
444 io_ctl->size -= sizeof(u64) +
445 (sizeof(u32) * io_ctl->num_pages);
446 } else {
447 io_ctl->cur += sizeof(u64);
448 io_ctl->size -= sizeof(u64) * 2;
449 }
450
451 gen = io_ctl->cur;
452 if (le64_to_cpu(*gen) != generation) {
453 printk_ratelimited(KERN_ERR "BTRFS: space cache generation "
454 "(%Lu) does not match inode (%Lu)\n", *gen,
455 generation);
456 io_ctl_unmap_page(io_ctl);
457 return -EIO;
458 }
459 io_ctl->cur += sizeof(u64);
460 return 0;
461 }
462
463 static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
464 {
465 u32 *tmp;
466 u32 crc = ~(u32)0;
467 unsigned offset = 0;
468
469 if (!io_ctl->check_crcs) {
470 io_ctl_unmap_page(io_ctl);
471 return;
472 }
473
474 if (index == 0)
475 offset = sizeof(u32) * io_ctl->num_pages;
476
477 crc = btrfs_csum_data(io_ctl->orig + offset, crc,
478 PAGE_CACHE_SIZE - offset);
479 btrfs_csum_final(crc, (char *)&crc);
480 io_ctl_unmap_page(io_ctl);
481 tmp = page_address(io_ctl->pages[0]);
482 tmp += index;
483 *tmp = crc;
484 }
485
486 static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
487 {
488 u32 *tmp, val;
489 u32 crc = ~(u32)0;
490 unsigned offset = 0;
491
492 if (!io_ctl->check_crcs) {
493 io_ctl_map_page(io_ctl, 0);
494 return 0;
495 }
496
497 if (index == 0)
498 offset = sizeof(u32) * io_ctl->num_pages;
499
500 tmp = page_address(io_ctl->pages[0]);
501 tmp += index;
502 val = *tmp;
503
504 io_ctl_map_page(io_ctl, 0);
505 crc = btrfs_csum_data(io_ctl->orig + offset, crc,
506 PAGE_CACHE_SIZE - offset);
507 btrfs_csum_final(crc, (char *)&crc);
508 if (val != crc) {
509 printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free "
510 "space cache\n");
511 io_ctl_unmap_page(io_ctl);
512 return -EIO;
513 }
514
515 return 0;
516 }
517
518 static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
519 void *bitmap)
520 {
521 struct btrfs_free_space_entry *entry;
522
523 if (!io_ctl->cur)
524 return -ENOSPC;
525
526 entry = io_ctl->cur;
527 entry->offset = cpu_to_le64(offset);
528 entry->bytes = cpu_to_le64(bytes);
529 entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
530 BTRFS_FREE_SPACE_EXTENT;
531 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
532 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
533
534 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
535 return 0;
536
537 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
538
539 /* No more pages to map */
540 if (io_ctl->index >= io_ctl->num_pages)
541 return 0;
542
543 /* map the next page */
544 io_ctl_map_page(io_ctl, 1);
545 return 0;
546 }
547
548 static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
549 {
550 if (!io_ctl->cur)
551 return -ENOSPC;
552
553 /*
554 * If we aren't at the start of the current page, unmap this one and
555 * map the next one if there is any left.
556 */
557 if (io_ctl->cur != io_ctl->orig) {
558 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
559 if (io_ctl->index >= io_ctl->num_pages)
560 return -ENOSPC;
561 io_ctl_map_page(io_ctl, 0);
562 }
563
564 memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
565 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
566 if (io_ctl->index < io_ctl->num_pages)
567 io_ctl_map_page(io_ctl, 0);
568 return 0;
569 }
570
571 static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
572 {
573 /*
574 * If we're not on the boundary we know we've modified the page and we
575 * need to crc the page.
576 */
577 if (io_ctl->cur != io_ctl->orig)
578 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
579 else
580 io_ctl_unmap_page(io_ctl);
581
582 while (io_ctl->index < io_ctl->num_pages) {
583 io_ctl_map_page(io_ctl, 1);
584 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
585 }
586 }
587
588 static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
589 struct btrfs_free_space *entry, u8 *type)
590 {
591 struct btrfs_free_space_entry *e;
592 int ret;
593
594 if (!io_ctl->cur) {
595 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
596 if (ret)
597 return ret;
598 }
599
600 e = io_ctl->cur;
601 entry->offset = le64_to_cpu(e->offset);
602 entry->bytes = le64_to_cpu(e->bytes);
603 *type = e->type;
604 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
605 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
606
607 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
608 return 0;
609
610 io_ctl_unmap_page(io_ctl);
611
612 return 0;
613 }
614
615 static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
616 struct btrfs_free_space *entry)
617 {
618 int ret;
619
620 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
621 if (ret)
622 return ret;
623
624 memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
625 io_ctl_unmap_page(io_ctl);
626
627 return 0;
628 }
629
630 /*
631 * Since we attach pinned extents after the fact we can have contiguous sections
632 * of free space that are split up in entries. This poses a problem with the
633 * tree logging stuff since it could have allocated across what appears to be 2
634 * entries since we would have merged the entries when adding the pinned extents
635 * back to the free space cache. So run through the space cache that we just
636 * loaded and merge contiguous entries. This will make the log replay stuff not
637 * blow up and it will make for nicer allocator behavior.
638 */
639 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
640 {
641 struct btrfs_free_space *e, *prev = NULL;
642 struct rb_node *n;
643
644 again:
645 spin_lock(&ctl->tree_lock);
646 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
647 e = rb_entry(n, struct btrfs_free_space, offset_index);
648 if (!prev)
649 goto next;
650 if (e->bitmap || prev->bitmap)
651 goto next;
652 if (prev->offset + prev->bytes == e->offset) {
653 unlink_free_space(ctl, prev);
654 unlink_free_space(ctl, e);
655 prev->bytes += e->bytes;
656 kmem_cache_free(btrfs_free_space_cachep, e);
657 link_free_space(ctl, prev);
658 prev = NULL;
659 spin_unlock(&ctl->tree_lock);
660 goto again;
661 }
662 next:
663 prev = e;
664 }
665 spin_unlock(&ctl->tree_lock);
666 }
667
668 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
669 struct btrfs_free_space_ctl *ctl,
670 struct btrfs_path *path, u64 offset)
671 {
672 struct btrfs_free_space_header *header;
673 struct extent_buffer *leaf;
674 struct btrfs_io_ctl io_ctl;
675 struct btrfs_key key;
676 struct btrfs_free_space *e, *n;
677 LIST_HEAD(bitmaps);
678 u64 num_entries;
679 u64 num_bitmaps;
680 u64 generation;
681 u8 type;
682 int ret = 0;
683
684 /* Nothing in the space cache, goodbye */
685 if (!i_size_read(inode))
686 return 0;
687
688 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
689 key.offset = offset;
690 key.type = 0;
691
692 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
693 if (ret < 0)
694 return 0;
695 else if (ret > 0) {
696 btrfs_release_path(path);
697 return 0;
698 }
699
700 ret = -1;
701
702 leaf = path->nodes[0];
703 header = btrfs_item_ptr(leaf, path->slots[0],
704 struct btrfs_free_space_header);
705 num_entries = btrfs_free_space_entries(leaf, header);
706 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
707 generation = btrfs_free_space_generation(leaf, header);
708 btrfs_release_path(path);
709
710 if (!BTRFS_I(inode)->generation) {
711 btrfs_info(root->fs_info,
712 "The free space cache file (%llu) is invalid. skip it\n",
713 offset);
714 return 0;
715 }
716
717 if (BTRFS_I(inode)->generation != generation) {
718 btrfs_err(root->fs_info,
719 "free space inode generation (%llu) "
720 "did not match free space cache generation (%llu)",
721 BTRFS_I(inode)->generation, generation);
722 return 0;
723 }
724
725 if (!num_entries)
726 return 0;
727
728 ret = io_ctl_init(&io_ctl, inode, root, 0);
729 if (ret)
730 return ret;
731
732 ret = readahead_cache(inode);
733 if (ret)
734 goto out;
735
736 ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
737 if (ret)
738 goto out;
739
740 ret = io_ctl_check_crc(&io_ctl, 0);
741 if (ret)
742 goto free_cache;
743
744 ret = io_ctl_check_generation(&io_ctl, generation);
745 if (ret)
746 goto free_cache;
747
748 while (num_entries) {
749 e = kmem_cache_zalloc(btrfs_free_space_cachep,
750 GFP_NOFS);
751 if (!e)
752 goto free_cache;
753
754 ret = io_ctl_read_entry(&io_ctl, e, &type);
755 if (ret) {
756 kmem_cache_free(btrfs_free_space_cachep, e);
757 goto free_cache;
758 }
759
760 if (!e->bytes) {
761 kmem_cache_free(btrfs_free_space_cachep, e);
762 goto free_cache;
763 }
764
765 if (type == BTRFS_FREE_SPACE_EXTENT) {
766 spin_lock(&ctl->tree_lock);
767 ret = link_free_space(ctl, e);
768 spin_unlock(&ctl->tree_lock);
769 if (ret) {
770 btrfs_err(root->fs_info,
771 "Duplicate entries in free space cache, dumping");
772 kmem_cache_free(btrfs_free_space_cachep, e);
773 goto free_cache;
774 }
775 } else {
776 ASSERT(num_bitmaps);
777 num_bitmaps--;
778 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
779 if (!e->bitmap) {
780 kmem_cache_free(
781 btrfs_free_space_cachep, e);
782 goto free_cache;
783 }
784 spin_lock(&ctl->tree_lock);
785 ret = link_free_space(ctl, e);
786 ctl->total_bitmaps++;
787 ctl->op->recalc_thresholds(ctl);
788 spin_unlock(&ctl->tree_lock);
789 if (ret) {
790 btrfs_err(root->fs_info,
791 "Duplicate entries in free space cache, dumping");
792 kmem_cache_free(btrfs_free_space_cachep, e);
793 goto free_cache;
794 }
795 list_add_tail(&e->list, &bitmaps);
796 }
797
798 num_entries--;
799 }
800
801 io_ctl_unmap_page(&io_ctl);
802
803 /*
804 * We add the bitmaps at the end of the entries in order that
805 * the bitmap entries are added to the cache.
806 */
807 list_for_each_entry_safe(e, n, &bitmaps, list) {
808 list_del_init(&e->list);
809 ret = io_ctl_read_bitmap(&io_ctl, e);
810 if (ret)
811 goto free_cache;
812 }
813
814 io_ctl_drop_pages(&io_ctl);
815 merge_space_tree(ctl);
816 ret = 1;
817 out:
818 io_ctl_free(&io_ctl);
819 return ret;
820 free_cache:
821 io_ctl_drop_pages(&io_ctl);
822 __btrfs_remove_free_space_cache(ctl);
823 goto out;
824 }
825
826 int load_free_space_cache(struct btrfs_fs_info *fs_info,
827 struct btrfs_block_group_cache *block_group)
828 {
829 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
830 struct btrfs_root *root = fs_info->tree_root;
831 struct inode *inode;
832 struct btrfs_path *path;
833 int ret = 0;
834 bool matched;
835 u64 used = btrfs_block_group_used(&block_group->item);
836
837 /*
838 * If this block group has been marked to be cleared for one reason or
839 * another then we can't trust the on disk cache, so just return.
840 */
841 spin_lock(&block_group->lock);
842 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
843 spin_unlock(&block_group->lock);
844 return 0;
845 }
846 spin_unlock(&block_group->lock);
847
848 path = btrfs_alloc_path();
849 if (!path)
850 return 0;
851 path->search_commit_root = 1;
852 path->skip_locking = 1;
853
854 inode = lookup_free_space_inode(root, block_group, path);
855 if (IS_ERR(inode)) {
856 btrfs_free_path(path);
857 return 0;
858 }
859
860 /* We may have converted the inode and made the cache invalid. */
861 spin_lock(&block_group->lock);
862 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
863 spin_unlock(&block_group->lock);
864 btrfs_free_path(path);
865 goto out;
866 }
867 spin_unlock(&block_group->lock);
868
869 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
870 path, block_group->key.objectid);
871 btrfs_free_path(path);
872 if (ret <= 0)
873 goto out;
874
875 spin_lock(&ctl->tree_lock);
876 matched = (ctl->free_space == (block_group->key.offset - used -
877 block_group->bytes_super));
878 spin_unlock(&ctl->tree_lock);
879
880 if (!matched) {
881 __btrfs_remove_free_space_cache(ctl);
882 btrfs_warn(fs_info, "block group %llu has wrong amount of free space",
883 block_group->key.objectid);
884 ret = -1;
885 }
886 out:
887 if (ret < 0) {
888 /* This cache is bogus, make sure it gets cleared */
889 spin_lock(&block_group->lock);
890 block_group->disk_cache_state = BTRFS_DC_CLEAR;
891 spin_unlock(&block_group->lock);
892 ret = 0;
893
894 btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now",
895 block_group->key.objectid);
896 }
897
898 iput(inode);
899 return ret;
900 }
901
902 static noinline_for_stack
903 int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
904 struct btrfs_free_space_ctl *ctl,
905 struct btrfs_block_group_cache *block_group,
906 int *entries, int *bitmaps,
907 struct list_head *bitmap_list)
908 {
909 int ret;
910 struct btrfs_free_cluster *cluster = NULL;
911 struct btrfs_free_cluster *cluster_locked = NULL;
912 struct rb_node *node = rb_first(&ctl->free_space_offset);
913 struct btrfs_trim_range *trim_entry;
914
915 /* Get the cluster for this block_group if it exists */
916 if (block_group && !list_empty(&block_group->cluster_list)) {
917 cluster = list_entry(block_group->cluster_list.next,
918 struct btrfs_free_cluster,
919 block_group_list);
920 }
921
922 if (!node && cluster) {
923 cluster_locked = cluster;
924 spin_lock(&cluster_locked->lock);
925 node = rb_first(&cluster->root);
926 cluster = NULL;
927 }
928
929 /* Write out the extent entries */
930 while (node) {
931 struct btrfs_free_space *e;
932
933 e = rb_entry(node, struct btrfs_free_space, offset_index);
934 *entries += 1;
935
936 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
937 e->bitmap);
938 if (ret)
939 goto fail;
940
941 if (e->bitmap) {
942 list_add_tail(&e->list, bitmap_list);
943 *bitmaps += 1;
944 }
945 node = rb_next(node);
946 if (!node && cluster) {
947 node = rb_first(&cluster->root);
948 cluster_locked = cluster;
949 spin_lock(&cluster_locked->lock);
950 cluster = NULL;
951 }
952 }
953 if (cluster_locked) {
954 spin_unlock(&cluster_locked->lock);
955 cluster_locked = NULL;
956 }
957
958 /*
959 * Make sure we don't miss any range that was removed from our rbtree
960 * because trimming is running. Otherwise after a umount+mount (or crash
961 * after committing the transaction) we would leak free space and get
962 * an inconsistent free space cache report from fsck.
963 */
964 list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
965 ret = io_ctl_add_entry(io_ctl, trim_entry->start,
966 trim_entry->bytes, NULL);
967 if (ret)
968 goto fail;
969 *entries += 1;
970 }
971
972 return 0;
973 fail:
974 if (cluster_locked)
975 spin_unlock(&cluster_locked->lock);
976 return -ENOSPC;
977 }
978
979 static noinline_for_stack int
980 update_cache_item(struct btrfs_trans_handle *trans,
981 struct btrfs_root *root,
982 struct inode *inode,
983 struct btrfs_path *path, u64 offset,
984 int entries, int bitmaps)
985 {
986 struct btrfs_key key;
987 struct btrfs_free_space_header *header;
988 struct extent_buffer *leaf;
989 int ret;
990
991 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
992 key.offset = offset;
993 key.type = 0;
994
995 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
996 if (ret < 0) {
997 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
998 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
999 GFP_NOFS);
1000 goto fail;
1001 }
1002 leaf = path->nodes[0];
1003 if (ret > 0) {
1004 struct btrfs_key found_key;
1005 ASSERT(path->slots[0]);
1006 path->slots[0]--;
1007 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1008 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1009 found_key.offset != offset) {
1010 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1011 inode->i_size - 1,
1012 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1013 NULL, GFP_NOFS);
1014 btrfs_release_path(path);
1015 goto fail;
1016 }
1017 }
1018
1019 BTRFS_I(inode)->generation = trans->transid;
1020 header = btrfs_item_ptr(leaf, path->slots[0],
1021 struct btrfs_free_space_header);
1022 btrfs_set_free_space_entries(leaf, header, entries);
1023 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1024 btrfs_set_free_space_generation(leaf, header, trans->transid);
1025 btrfs_mark_buffer_dirty(leaf);
1026 btrfs_release_path(path);
1027
1028 return 0;
1029
1030 fail:
1031 return -1;
1032 }
1033
1034 static noinline_for_stack int
1035 write_pinned_extent_entries(struct btrfs_root *root,
1036 struct btrfs_block_group_cache *block_group,
1037 struct btrfs_io_ctl *io_ctl,
1038 int *entries)
1039 {
1040 u64 start, extent_start, extent_end, len;
1041 struct extent_io_tree *unpin = NULL;
1042 int ret;
1043
1044 if (!block_group)
1045 return 0;
1046
1047 /*
1048 * We want to add any pinned extents to our free space cache
1049 * so we don't leak the space
1050 *
1051 * We shouldn't have switched the pinned extents yet so this is the
1052 * right one
1053 */
1054 unpin = root->fs_info->pinned_extents;
1055
1056 start = block_group->key.objectid;
1057
1058 while (start < block_group->key.objectid + block_group->key.offset) {
1059 ret = find_first_extent_bit(unpin, start,
1060 &extent_start, &extent_end,
1061 EXTENT_DIRTY, NULL);
1062 if (ret)
1063 return 0;
1064
1065 /* This pinned extent is out of our range */
1066 if (extent_start >= block_group->key.objectid +
1067 block_group->key.offset)
1068 return 0;
1069
1070 extent_start = max(extent_start, start);
1071 extent_end = min(block_group->key.objectid +
1072 block_group->key.offset, extent_end + 1);
1073 len = extent_end - extent_start;
1074
1075 *entries += 1;
1076 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1077 if (ret)
1078 return -ENOSPC;
1079
1080 start = extent_end;
1081 }
1082
1083 return 0;
1084 }
1085
1086 static noinline_for_stack int
1087 write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1088 {
1089 struct list_head *pos, *n;
1090 int ret;
1091
1092 /* Write out the bitmaps */
1093 list_for_each_safe(pos, n, bitmap_list) {
1094 struct btrfs_free_space *entry =
1095 list_entry(pos, struct btrfs_free_space, list);
1096
1097 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1098 if (ret)
1099 return -ENOSPC;
1100 list_del_init(&entry->list);
1101 }
1102
1103 return 0;
1104 }
1105
1106 static int flush_dirty_cache(struct inode *inode)
1107 {
1108 int ret;
1109
1110 ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1111 if (ret)
1112 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1113 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1114 GFP_NOFS);
1115
1116 return ret;
1117 }
1118
1119 static void noinline_for_stack
1120 cleanup_bitmap_list(struct list_head *bitmap_list)
1121 {
1122 struct list_head *pos, *n;
1123
1124 list_for_each_safe(pos, n, bitmap_list) {
1125 struct btrfs_free_space *entry =
1126 list_entry(pos, struct btrfs_free_space, list);
1127 list_del_init(&entry->list);
1128 }
1129 }
1130
1131 static void noinline_for_stack
1132 cleanup_write_cache_enospc(struct inode *inode,
1133 struct btrfs_io_ctl *io_ctl,
1134 struct extent_state **cached_state,
1135 struct list_head *bitmap_list)
1136 {
1137 io_ctl_drop_pages(io_ctl);
1138 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1139 i_size_read(inode) - 1, cached_state,
1140 GFP_NOFS);
1141 }
1142
1143 int btrfs_wait_cache_io(struct btrfs_root *root,
1144 struct btrfs_trans_handle *trans,
1145 struct btrfs_block_group_cache *block_group,
1146 struct btrfs_io_ctl *io_ctl,
1147 struct btrfs_path *path, u64 offset)
1148 {
1149 int ret;
1150 struct inode *inode = io_ctl->inode;
1151
1152 if (!inode)
1153 return 0;
1154
1155 if (block_group)
1156 root = root->fs_info->tree_root;
1157
1158 /* Flush the dirty pages in the cache file. */
1159 ret = flush_dirty_cache(inode);
1160 if (ret)
1161 goto out;
1162
1163 /* Update the cache item to tell everyone this cache file is valid. */
1164 ret = update_cache_item(trans, root, inode, path, offset,
1165 io_ctl->entries, io_ctl->bitmaps);
1166 out:
1167 io_ctl_free(io_ctl);
1168 if (ret) {
1169 invalidate_inode_pages2(inode->i_mapping);
1170 BTRFS_I(inode)->generation = 0;
1171 if (block_group) {
1172 #ifdef DEBUG
1173 btrfs_err(root->fs_info,
1174 "failed to write free space cache for block group %llu",
1175 block_group->key.objectid);
1176 #endif
1177 }
1178 }
1179 btrfs_update_inode(trans, root, inode);
1180
1181 if (block_group) {
1182 /* the dirty list is protected by the dirty_bgs_lock */
1183 spin_lock(&trans->transaction->dirty_bgs_lock);
1184
1185 /* the disk_cache_state is protected by the block group lock */
1186 spin_lock(&block_group->lock);
1187
1188 /*
1189 * only mark this as written if we didn't get put back on
1190 * the dirty list while waiting for IO. Otherwise our
1191 * cache state won't be right, and we won't get written again
1192 */
1193 if (!ret && list_empty(&block_group->dirty_list))
1194 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1195 else if (ret)
1196 block_group->disk_cache_state = BTRFS_DC_ERROR;
1197
1198 spin_unlock(&block_group->lock);
1199 spin_unlock(&trans->transaction->dirty_bgs_lock);
1200 io_ctl->inode = NULL;
1201 iput(inode);
1202 }
1203
1204 return ret;
1205
1206 }
1207
1208 /**
1209 * __btrfs_write_out_cache - write out cached info to an inode
1210 * @root - the root the inode belongs to
1211 * @ctl - the free space cache we are going to write out
1212 * @block_group - the block_group for this cache if it belongs to a block_group
1213 * @trans - the trans handle
1214 * @path - the path to use
1215 * @offset - the offset for the key we'll insert
1216 *
1217 * This function writes out a free space cache struct to disk for quick recovery
1218 * on mount. This will return 0 if it was successfull in writing the cache out,
1219 * or an errno if it was not.
1220 */
1221 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1222 struct btrfs_free_space_ctl *ctl,
1223 struct btrfs_block_group_cache *block_group,
1224 struct btrfs_io_ctl *io_ctl,
1225 struct btrfs_trans_handle *trans,
1226 struct btrfs_path *path, u64 offset)
1227 {
1228 struct extent_state *cached_state = NULL;
1229 LIST_HEAD(bitmap_list);
1230 int entries = 0;
1231 int bitmaps = 0;
1232 int ret;
1233 int must_iput = 0;
1234
1235 if (!i_size_read(inode))
1236 return -EIO;
1237
1238 WARN_ON(io_ctl->pages);
1239 ret = io_ctl_init(io_ctl, inode, root, 1);
1240 if (ret)
1241 return ret;
1242
1243 if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1244 down_write(&block_group->data_rwsem);
1245 spin_lock(&block_group->lock);
1246 if (block_group->delalloc_bytes) {
1247 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1248 spin_unlock(&block_group->lock);
1249 up_write(&block_group->data_rwsem);
1250 BTRFS_I(inode)->generation = 0;
1251 ret = 0;
1252 must_iput = 1;
1253 goto out;
1254 }
1255 spin_unlock(&block_group->lock);
1256 }
1257
1258 /* Lock all pages first so we can lock the extent safely. */
1259 ret = io_ctl_prepare_pages(io_ctl, inode, 0);
1260 if (ret)
1261 goto out;
1262
1263 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1264 0, &cached_state);
1265
1266 io_ctl_set_generation(io_ctl, trans->transid);
1267
1268 mutex_lock(&ctl->cache_writeout_mutex);
1269 /* Write out the extent entries in the free space cache */
1270 spin_lock(&ctl->tree_lock);
1271 ret = write_cache_extent_entries(io_ctl, ctl,
1272 block_group, &entries, &bitmaps,
1273 &bitmap_list);
1274 if (ret)
1275 goto out_nospc_locked;
1276
1277 /*
1278 * Some spaces that are freed in the current transaction are pinned,
1279 * they will be added into free space cache after the transaction is
1280 * committed, we shouldn't lose them.
1281 *
1282 * If this changes while we are working we'll get added back to
1283 * the dirty list and redo it. No locking needed
1284 */
1285 ret = write_pinned_extent_entries(root, block_group, io_ctl, &entries);
1286 if (ret)
1287 goto out_nospc_locked;
1288
1289 /*
1290 * At last, we write out all the bitmaps and keep cache_writeout_mutex
1291 * locked while doing it because a concurrent trim can be manipulating
1292 * or freeing the bitmap.
1293 */
1294 ret = write_bitmap_entries(io_ctl, &bitmap_list);
1295 spin_unlock(&ctl->tree_lock);
1296 mutex_unlock(&ctl->cache_writeout_mutex);
1297 if (ret)
1298 goto out_nospc;
1299
1300 /* Zero out the rest of the pages just to make sure */
1301 io_ctl_zero_remaining_pages(io_ctl);
1302
1303 /* Everything is written out, now we dirty the pages in the file. */
1304 ret = btrfs_dirty_pages(root, inode, io_ctl->pages, io_ctl->num_pages,
1305 0, i_size_read(inode), &cached_state);
1306 if (ret)
1307 goto out_nospc;
1308
1309 if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1310 up_write(&block_group->data_rwsem);
1311 /*
1312 * Release the pages and unlock the extent, we will flush
1313 * them out later
1314 */
1315 io_ctl_drop_pages(io_ctl);
1316
1317 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1318 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1319
1320 /*
1321 * at this point the pages are under IO and we're happy,
1322 * The caller is responsible for waiting on them and updating the
1323 * the cache and the inode
1324 */
1325 io_ctl->entries = entries;
1326 io_ctl->bitmaps = bitmaps;
1327
1328 ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
1329 if (ret)
1330 goto out;
1331
1332 return 0;
1333
1334 out:
1335 io_ctl->inode = NULL;
1336 io_ctl_free(io_ctl);
1337 if (ret) {
1338 invalidate_inode_pages2(inode->i_mapping);
1339 BTRFS_I(inode)->generation = 0;
1340 }
1341 btrfs_update_inode(trans, root, inode);
1342 if (must_iput)
1343 iput(inode);
1344 return ret;
1345
1346 out_nospc_locked:
1347 cleanup_bitmap_list(&bitmap_list);
1348 spin_unlock(&ctl->tree_lock);
1349 mutex_unlock(&ctl->cache_writeout_mutex);
1350
1351 out_nospc:
1352 cleanup_write_cache_enospc(inode, io_ctl, &cached_state, &bitmap_list);
1353
1354 if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1355 up_write(&block_group->data_rwsem);
1356
1357 goto out;
1358 }
1359
1360 int btrfs_write_out_cache(struct btrfs_root *root,
1361 struct btrfs_trans_handle *trans,
1362 struct btrfs_block_group_cache *block_group,
1363 struct btrfs_path *path)
1364 {
1365 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1366 struct inode *inode;
1367 int ret = 0;
1368
1369 root = root->fs_info->tree_root;
1370
1371 spin_lock(&block_group->lock);
1372 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1373 spin_unlock(&block_group->lock);
1374 return 0;
1375 }
1376 spin_unlock(&block_group->lock);
1377
1378 inode = lookup_free_space_inode(root, block_group, path);
1379 if (IS_ERR(inode))
1380 return 0;
1381
1382 ret = __btrfs_write_out_cache(root, inode, ctl, block_group,
1383 &block_group->io_ctl, trans,
1384 path, block_group->key.objectid);
1385 if (ret) {
1386 #ifdef DEBUG
1387 btrfs_err(root->fs_info,
1388 "failed to write free space cache for block group %llu",
1389 block_group->key.objectid);
1390 #endif
1391 spin_lock(&block_group->lock);
1392 block_group->disk_cache_state = BTRFS_DC_ERROR;
1393 spin_unlock(&block_group->lock);
1394
1395 block_group->io_ctl.inode = NULL;
1396 iput(inode);
1397 }
1398
1399 /*
1400 * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1401 * to wait for IO and put the inode
1402 */
1403
1404 return ret;
1405 }
1406
1407 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1408 u64 offset)
1409 {
1410 ASSERT(offset >= bitmap_start);
1411 offset -= bitmap_start;
1412 return (unsigned long)(div_u64(offset, unit));
1413 }
1414
1415 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1416 {
1417 return (unsigned long)(div_u64(bytes, unit));
1418 }
1419
1420 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1421 u64 offset)
1422 {
1423 u64 bitmap_start;
1424 u32 bytes_per_bitmap;
1425
1426 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1427 bitmap_start = offset - ctl->start;
1428 bitmap_start = div_u64(bitmap_start, bytes_per_bitmap);
1429 bitmap_start *= bytes_per_bitmap;
1430 bitmap_start += ctl->start;
1431
1432 return bitmap_start;
1433 }
1434
1435 static int tree_insert_offset(struct rb_root *root, u64 offset,
1436 struct rb_node *node, int bitmap)
1437 {
1438 struct rb_node **p = &root->rb_node;
1439 struct rb_node *parent = NULL;
1440 struct btrfs_free_space *info;
1441
1442 while (*p) {
1443 parent = *p;
1444 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1445
1446 if (offset < info->offset) {
1447 p = &(*p)->rb_left;
1448 } else if (offset > info->offset) {
1449 p = &(*p)->rb_right;
1450 } else {
1451 /*
1452 * we could have a bitmap entry and an extent entry
1453 * share the same offset. If this is the case, we want
1454 * the extent entry to always be found first if we do a
1455 * linear search through the tree, since we want to have
1456 * the quickest allocation time, and allocating from an
1457 * extent is faster than allocating from a bitmap. So
1458 * if we're inserting a bitmap and we find an entry at
1459 * this offset, we want to go right, or after this entry
1460 * logically. If we are inserting an extent and we've
1461 * found a bitmap, we want to go left, or before
1462 * logically.
1463 */
1464 if (bitmap) {
1465 if (info->bitmap) {
1466 WARN_ON_ONCE(1);
1467 return -EEXIST;
1468 }
1469 p = &(*p)->rb_right;
1470 } else {
1471 if (!info->bitmap) {
1472 WARN_ON_ONCE(1);
1473 return -EEXIST;
1474 }
1475 p = &(*p)->rb_left;
1476 }
1477 }
1478 }
1479
1480 rb_link_node(node, parent, p);
1481 rb_insert_color(node, root);
1482
1483 return 0;
1484 }
1485
1486 /*
1487 * searches the tree for the given offset.
1488 *
1489 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1490 * want a section that has at least bytes size and comes at or after the given
1491 * offset.
1492 */
1493 static struct btrfs_free_space *
1494 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1495 u64 offset, int bitmap_only, int fuzzy)
1496 {
1497 struct rb_node *n = ctl->free_space_offset.rb_node;
1498 struct btrfs_free_space *entry, *prev = NULL;
1499
1500 /* find entry that is closest to the 'offset' */
1501 while (1) {
1502 if (!n) {
1503 entry = NULL;
1504 break;
1505 }
1506
1507 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1508 prev = entry;
1509
1510 if (offset < entry->offset)
1511 n = n->rb_left;
1512 else if (offset > entry->offset)
1513 n = n->rb_right;
1514 else
1515 break;
1516 }
1517
1518 if (bitmap_only) {
1519 if (!entry)
1520 return NULL;
1521 if (entry->bitmap)
1522 return entry;
1523
1524 /*
1525 * bitmap entry and extent entry may share same offset,
1526 * in that case, bitmap entry comes after extent entry.
1527 */
1528 n = rb_next(n);
1529 if (!n)
1530 return NULL;
1531 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1532 if (entry->offset != offset)
1533 return NULL;
1534
1535 WARN_ON(!entry->bitmap);
1536 return entry;
1537 } else if (entry) {
1538 if (entry->bitmap) {
1539 /*
1540 * if previous extent entry covers the offset,
1541 * we should return it instead of the bitmap entry
1542 */
1543 n = rb_prev(&entry->offset_index);
1544 if (n) {
1545 prev = rb_entry(n, struct btrfs_free_space,
1546 offset_index);
1547 if (!prev->bitmap &&
1548 prev->offset + prev->bytes > offset)
1549 entry = prev;
1550 }
1551 }
1552 return entry;
1553 }
1554
1555 if (!prev)
1556 return NULL;
1557
1558 /* find last entry before the 'offset' */
1559 entry = prev;
1560 if (entry->offset > offset) {
1561 n = rb_prev(&entry->offset_index);
1562 if (n) {
1563 entry = rb_entry(n, struct btrfs_free_space,
1564 offset_index);
1565 ASSERT(entry->offset <= offset);
1566 } else {
1567 if (fuzzy)
1568 return entry;
1569 else
1570 return NULL;
1571 }
1572 }
1573
1574 if (entry->bitmap) {
1575 n = rb_prev(&entry->offset_index);
1576 if (n) {
1577 prev = rb_entry(n, struct btrfs_free_space,
1578 offset_index);
1579 if (!prev->bitmap &&
1580 prev->offset + prev->bytes > offset)
1581 return prev;
1582 }
1583 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1584 return entry;
1585 } else if (entry->offset + entry->bytes > offset)
1586 return entry;
1587
1588 if (!fuzzy)
1589 return NULL;
1590
1591 while (1) {
1592 if (entry->bitmap) {
1593 if (entry->offset + BITS_PER_BITMAP *
1594 ctl->unit > offset)
1595 break;
1596 } else {
1597 if (entry->offset + entry->bytes > offset)
1598 break;
1599 }
1600
1601 n = rb_next(&entry->offset_index);
1602 if (!n)
1603 return NULL;
1604 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1605 }
1606 return entry;
1607 }
1608
1609 static inline void
1610 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1611 struct btrfs_free_space *info)
1612 {
1613 rb_erase(&info->offset_index, &ctl->free_space_offset);
1614 ctl->free_extents--;
1615 }
1616
1617 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1618 struct btrfs_free_space *info)
1619 {
1620 __unlink_free_space(ctl, info);
1621 ctl->free_space -= info->bytes;
1622 }
1623
1624 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1625 struct btrfs_free_space *info)
1626 {
1627 int ret = 0;
1628
1629 ASSERT(info->bytes || info->bitmap);
1630 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1631 &info->offset_index, (info->bitmap != NULL));
1632 if (ret)
1633 return ret;
1634
1635 ctl->free_space += info->bytes;
1636 ctl->free_extents++;
1637 return ret;
1638 }
1639
1640 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1641 {
1642 struct btrfs_block_group_cache *block_group = ctl->private;
1643 u64 max_bytes;
1644 u64 bitmap_bytes;
1645 u64 extent_bytes;
1646 u64 size = block_group->key.offset;
1647 u32 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1648 u32 max_bitmaps = div_u64(size + bytes_per_bg - 1, bytes_per_bg);
1649
1650 max_bitmaps = max_t(u32, max_bitmaps, 1);
1651
1652 ASSERT(ctl->total_bitmaps <= max_bitmaps);
1653
1654 /*
1655 * The goal is to keep the total amount of memory used per 1gb of space
1656 * at or below 32k, so we need to adjust how much memory we allow to be
1657 * used by extent based free space tracking
1658 */
1659 if (size < 1024 * 1024 * 1024)
1660 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1661 else
1662 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1663 div_u64(size, 1024 * 1024 * 1024);
1664
1665 /*
1666 * we want to account for 1 more bitmap than what we have so we can make
1667 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1668 * we add more bitmaps.
1669 */
1670 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1671
1672 if (bitmap_bytes >= max_bytes) {
1673 ctl->extents_thresh = 0;
1674 return;
1675 }
1676
1677 /*
1678 * we want the extent entry threshold to always be at most 1/2 the max
1679 * bytes we can have, or whatever is less than that.
1680 */
1681 extent_bytes = max_bytes - bitmap_bytes;
1682 extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
1683
1684 ctl->extents_thresh =
1685 div_u64(extent_bytes, sizeof(struct btrfs_free_space));
1686 }
1687
1688 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1689 struct btrfs_free_space *info,
1690 u64 offset, u64 bytes)
1691 {
1692 unsigned long start, count;
1693
1694 start = offset_to_bit(info->offset, ctl->unit, offset);
1695 count = bytes_to_bits(bytes, ctl->unit);
1696 ASSERT(start + count <= BITS_PER_BITMAP);
1697
1698 bitmap_clear(info->bitmap, start, count);
1699
1700 info->bytes -= bytes;
1701 }
1702
1703 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1704 struct btrfs_free_space *info, u64 offset,
1705 u64 bytes)
1706 {
1707 __bitmap_clear_bits(ctl, info, offset, bytes);
1708 ctl->free_space -= bytes;
1709 }
1710
1711 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1712 struct btrfs_free_space *info, u64 offset,
1713 u64 bytes)
1714 {
1715 unsigned long start, count;
1716
1717 start = offset_to_bit(info->offset, ctl->unit, offset);
1718 count = bytes_to_bits(bytes, ctl->unit);
1719 ASSERT(start + count <= BITS_PER_BITMAP);
1720
1721 bitmap_set(info->bitmap, start, count);
1722
1723 info->bytes += bytes;
1724 ctl->free_space += bytes;
1725 }
1726
1727 /*
1728 * If we can not find suitable extent, we will use bytes to record
1729 * the size of the max extent.
1730 */
1731 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1732 struct btrfs_free_space *bitmap_info, u64 *offset,
1733 u64 *bytes)
1734 {
1735 unsigned long found_bits = 0;
1736 unsigned long max_bits = 0;
1737 unsigned long bits, i;
1738 unsigned long next_zero;
1739 unsigned long extent_bits;
1740
1741 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1742 max_t(u64, *offset, bitmap_info->offset));
1743 bits = bytes_to_bits(*bytes, ctl->unit);
1744
1745 for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1746 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1747 BITS_PER_BITMAP, i);
1748 extent_bits = next_zero - i;
1749 if (extent_bits >= bits) {
1750 found_bits = extent_bits;
1751 break;
1752 } else if (extent_bits > max_bits) {
1753 max_bits = extent_bits;
1754 }
1755 i = next_zero;
1756 }
1757
1758 if (found_bits) {
1759 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1760 *bytes = (u64)(found_bits) * ctl->unit;
1761 return 0;
1762 }
1763
1764 *bytes = (u64)(max_bits) * ctl->unit;
1765 return -1;
1766 }
1767
1768 /* Cache the size of the max extent in bytes */
1769 static struct btrfs_free_space *
1770 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1771 unsigned long align, u64 *max_extent_size)
1772 {
1773 struct btrfs_free_space *entry;
1774 struct rb_node *node;
1775 u64 tmp;
1776 u64 align_off;
1777 int ret;
1778
1779 if (!ctl->free_space_offset.rb_node)
1780 goto out;
1781
1782 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1783 if (!entry)
1784 goto out;
1785
1786 for (node = &entry->offset_index; node; node = rb_next(node)) {
1787 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1788 if (entry->bytes < *bytes) {
1789 if (entry->bytes > *max_extent_size)
1790 *max_extent_size = entry->bytes;
1791 continue;
1792 }
1793
1794 /* make sure the space returned is big enough
1795 * to match our requested alignment
1796 */
1797 if (*bytes >= align) {
1798 tmp = entry->offset - ctl->start + align - 1;
1799 tmp = div64_u64(tmp, align);
1800 tmp = tmp * align + ctl->start;
1801 align_off = tmp - entry->offset;
1802 } else {
1803 align_off = 0;
1804 tmp = entry->offset;
1805 }
1806
1807 if (entry->bytes < *bytes + align_off) {
1808 if (entry->bytes > *max_extent_size)
1809 *max_extent_size = entry->bytes;
1810 continue;
1811 }
1812
1813 if (entry->bitmap) {
1814 u64 size = *bytes;
1815
1816 ret = search_bitmap(ctl, entry, &tmp, &size);
1817 if (!ret) {
1818 *offset = tmp;
1819 *bytes = size;
1820 return entry;
1821 } else if (size > *max_extent_size) {
1822 *max_extent_size = size;
1823 }
1824 continue;
1825 }
1826
1827 *offset = tmp;
1828 *bytes = entry->bytes - align_off;
1829 return entry;
1830 }
1831 out:
1832 return NULL;
1833 }
1834
1835 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1836 struct btrfs_free_space *info, u64 offset)
1837 {
1838 info->offset = offset_to_bitmap(ctl, offset);
1839 info->bytes = 0;
1840 INIT_LIST_HEAD(&info->list);
1841 link_free_space(ctl, info);
1842 ctl->total_bitmaps++;
1843
1844 ctl->op->recalc_thresholds(ctl);
1845 }
1846
1847 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1848 struct btrfs_free_space *bitmap_info)
1849 {
1850 unlink_free_space(ctl, bitmap_info);
1851 kfree(bitmap_info->bitmap);
1852 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1853 ctl->total_bitmaps--;
1854 ctl->op->recalc_thresholds(ctl);
1855 }
1856
1857 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1858 struct btrfs_free_space *bitmap_info,
1859 u64 *offset, u64 *bytes)
1860 {
1861 u64 end;
1862 u64 search_start, search_bytes;
1863 int ret;
1864
1865 again:
1866 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1867
1868 /*
1869 * We need to search for bits in this bitmap. We could only cover some
1870 * of the extent in this bitmap thanks to how we add space, so we need
1871 * to search for as much as it as we can and clear that amount, and then
1872 * go searching for the next bit.
1873 */
1874 search_start = *offset;
1875 search_bytes = ctl->unit;
1876 search_bytes = min(search_bytes, end - search_start + 1);
1877 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1878 if (ret < 0 || search_start != *offset)
1879 return -EINVAL;
1880
1881 /* We may have found more bits than what we need */
1882 search_bytes = min(search_bytes, *bytes);
1883
1884 /* Cannot clear past the end of the bitmap */
1885 search_bytes = min(search_bytes, end - search_start + 1);
1886
1887 bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1888 *offset += search_bytes;
1889 *bytes -= search_bytes;
1890
1891 if (*bytes) {
1892 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1893 if (!bitmap_info->bytes)
1894 free_bitmap(ctl, bitmap_info);
1895
1896 /*
1897 * no entry after this bitmap, but we still have bytes to
1898 * remove, so something has gone wrong.
1899 */
1900 if (!next)
1901 return -EINVAL;
1902
1903 bitmap_info = rb_entry(next, struct btrfs_free_space,
1904 offset_index);
1905
1906 /*
1907 * if the next entry isn't a bitmap we need to return to let the
1908 * extent stuff do its work.
1909 */
1910 if (!bitmap_info->bitmap)
1911 return -EAGAIN;
1912
1913 /*
1914 * Ok the next item is a bitmap, but it may not actually hold
1915 * the information for the rest of this free space stuff, so
1916 * look for it, and if we don't find it return so we can try
1917 * everything over again.
1918 */
1919 search_start = *offset;
1920 search_bytes = ctl->unit;
1921 ret = search_bitmap(ctl, bitmap_info, &search_start,
1922 &search_bytes);
1923 if (ret < 0 || search_start != *offset)
1924 return -EAGAIN;
1925
1926 goto again;
1927 } else if (!bitmap_info->bytes)
1928 free_bitmap(ctl, bitmap_info);
1929
1930 return 0;
1931 }
1932
1933 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1934 struct btrfs_free_space *info, u64 offset,
1935 u64 bytes)
1936 {
1937 u64 bytes_to_set = 0;
1938 u64 end;
1939
1940 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1941
1942 bytes_to_set = min(end - offset, bytes);
1943
1944 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1945
1946 return bytes_to_set;
1947
1948 }
1949
1950 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1951 struct btrfs_free_space *info)
1952 {
1953 struct btrfs_block_group_cache *block_group = ctl->private;
1954
1955 /*
1956 * If we are below the extents threshold then we can add this as an
1957 * extent, and don't have to deal with the bitmap
1958 */
1959 if (ctl->free_extents < ctl->extents_thresh) {
1960 /*
1961 * If this block group has some small extents we don't want to
1962 * use up all of our free slots in the cache with them, we want
1963 * to reserve them to larger extents, however if we have plent
1964 * of cache left then go ahead an dadd them, no sense in adding
1965 * the overhead of a bitmap if we don't have to.
1966 */
1967 if (info->bytes <= block_group->sectorsize * 4) {
1968 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1969 return false;
1970 } else {
1971 return false;
1972 }
1973 }
1974
1975 /*
1976 * The original block groups from mkfs can be really small, like 8
1977 * megabytes, so don't bother with a bitmap for those entries. However
1978 * some block groups can be smaller than what a bitmap would cover but
1979 * are still large enough that they could overflow the 32k memory limit,
1980 * so allow those block groups to still be allowed to have a bitmap
1981 * entry.
1982 */
1983 if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1984 return false;
1985
1986 return true;
1987 }
1988
1989 static struct btrfs_free_space_op free_space_op = {
1990 .recalc_thresholds = recalculate_thresholds,
1991 .use_bitmap = use_bitmap,
1992 };
1993
1994 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1995 struct btrfs_free_space *info)
1996 {
1997 struct btrfs_free_space *bitmap_info;
1998 struct btrfs_block_group_cache *block_group = NULL;
1999 int added = 0;
2000 u64 bytes, offset, bytes_added;
2001 int ret;
2002
2003 bytes = info->bytes;
2004 offset = info->offset;
2005
2006 if (!ctl->op->use_bitmap(ctl, info))
2007 return 0;
2008
2009 if (ctl->op == &free_space_op)
2010 block_group = ctl->private;
2011 again:
2012 /*
2013 * Since we link bitmaps right into the cluster we need to see if we
2014 * have a cluster here, and if so and it has our bitmap we need to add
2015 * the free space to that bitmap.
2016 */
2017 if (block_group && !list_empty(&block_group->cluster_list)) {
2018 struct btrfs_free_cluster *cluster;
2019 struct rb_node *node;
2020 struct btrfs_free_space *entry;
2021
2022 cluster = list_entry(block_group->cluster_list.next,
2023 struct btrfs_free_cluster,
2024 block_group_list);
2025 spin_lock(&cluster->lock);
2026 node = rb_first(&cluster->root);
2027 if (!node) {
2028 spin_unlock(&cluster->lock);
2029 goto no_cluster_bitmap;
2030 }
2031
2032 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2033 if (!entry->bitmap) {
2034 spin_unlock(&cluster->lock);
2035 goto no_cluster_bitmap;
2036 }
2037
2038 if (entry->offset == offset_to_bitmap(ctl, offset)) {
2039 bytes_added = add_bytes_to_bitmap(ctl, entry,
2040 offset, bytes);
2041 bytes -= bytes_added;
2042 offset += bytes_added;
2043 }
2044 spin_unlock(&cluster->lock);
2045 if (!bytes) {
2046 ret = 1;
2047 goto out;
2048 }
2049 }
2050
2051 no_cluster_bitmap:
2052 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2053 1, 0);
2054 if (!bitmap_info) {
2055 ASSERT(added == 0);
2056 goto new_bitmap;
2057 }
2058
2059 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
2060 bytes -= bytes_added;
2061 offset += bytes_added;
2062 added = 0;
2063
2064 if (!bytes) {
2065 ret = 1;
2066 goto out;
2067 } else
2068 goto again;
2069
2070 new_bitmap:
2071 if (info && info->bitmap) {
2072 add_new_bitmap(ctl, info, offset);
2073 added = 1;
2074 info = NULL;
2075 goto again;
2076 } else {
2077 spin_unlock(&ctl->tree_lock);
2078
2079 /* no pre-allocated info, allocate a new one */
2080 if (!info) {
2081 info = kmem_cache_zalloc(btrfs_free_space_cachep,
2082 GFP_NOFS);
2083 if (!info) {
2084 spin_lock(&ctl->tree_lock);
2085 ret = -ENOMEM;
2086 goto out;
2087 }
2088 }
2089
2090 /* allocate the bitmap */
2091 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
2092 spin_lock(&ctl->tree_lock);
2093 if (!info->bitmap) {
2094 ret = -ENOMEM;
2095 goto out;
2096 }
2097 goto again;
2098 }
2099
2100 out:
2101 if (info) {
2102 if (info->bitmap)
2103 kfree(info->bitmap);
2104 kmem_cache_free(btrfs_free_space_cachep, info);
2105 }
2106
2107 return ret;
2108 }
2109
2110 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2111 struct btrfs_free_space *info, bool update_stat)
2112 {
2113 struct btrfs_free_space *left_info;
2114 struct btrfs_free_space *right_info;
2115 bool merged = false;
2116 u64 offset = info->offset;
2117 u64 bytes = info->bytes;
2118
2119 /*
2120 * first we want to see if there is free space adjacent to the range we
2121 * are adding, if there is remove that struct and add a new one to
2122 * cover the entire range
2123 */
2124 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2125 if (right_info && rb_prev(&right_info->offset_index))
2126 left_info = rb_entry(rb_prev(&right_info->offset_index),
2127 struct btrfs_free_space, offset_index);
2128 else
2129 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2130
2131 if (right_info && !right_info->bitmap) {
2132 if (update_stat)
2133 unlink_free_space(ctl, right_info);
2134 else
2135 __unlink_free_space(ctl, right_info);
2136 info->bytes += right_info->bytes;
2137 kmem_cache_free(btrfs_free_space_cachep, right_info);
2138 merged = true;
2139 }
2140
2141 if (left_info && !left_info->bitmap &&
2142 left_info->offset + left_info->bytes == offset) {
2143 if (update_stat)
2144 unlink_free_space(ctl, left_info);
2145 else
2146 __unlink_free_space(ctl, left_info);
2147 info->offset = left_info->offset;
2148 info->bytes += left_info->bytes;
2149 kmem_cache_free(btrfs_free_space_cachep, left_info);
2150 merged = true;
2151 }
2152
2153 return merged;
2154 }
2155
2156 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2157 struct btrfs_free_space *info,
2158 bool update_stat)
2159 {
2160 struct btrfs_free_space *bitmap;
2161 unsigned long i;
2162 unsigned long j;
2163 const u64 end = info->offset + info->bytes;
2164 const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2165 u64 bytes;
2166
2167 bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2168 if (!bitmap)
2169 return false;
2170
2171 i = offset_to_bit(bitmap->offset, ctl->unit, end);
2172 j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2173 if (j == i)
2174 return false;
2175 bytes = (j - i) * ctl->unit;
2176 info->bytes += bytes;
2177
2178 if (update_stat)
2179 bitmap_clear_bits(ctl, bitmap, end, bytes);
2180 else
2181 __bitmap_clear_bits(ctl, bitmap, end, bytes);
2182
2183 if (!bitmap->bytes)
2184 free_bitmap(ctl, bitmap);
2185
2186 return true;
2187 }
2188
2189 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2190 struct btrfs_free_space *info,
2191 bool update_stat)
2192 {
2193 struct btrfs_free_space *bitmap;
2194 u64 bitmap_offset;
2195 unsigned long i;
2196 unsigned long j;
2197 unsigned long prev_j;
2198 u64 bytes;
2199
2200 bitmap_offset = offset_to_bitmap(ctl, info->offset);
2201 /* If we're on a boundary, try the previous logical bitmap. */
2202 if (bitmap_offset == info->offset) {
2203 if (info->offset == 0)
2204 return false;
2205 bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2206 }
2207
2208 bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2209 if (!bitmap)
2210 return false;
2211
2212 i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2213 j = 0;
2214 prev_j = (unsigned long)-1;
2215 for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2216 if (j > i)
2217 break;
2218 prev_j = j;
2219 }
2220 if (prev_j == i)
2221 return false;
2222
2223 if (prev_j == (unsigned long)-1)
2224 bytes = (i + 1) * ctl->unit;
2225 else
2226 bytes = (i - prev_j) * ctl->unit;
2227
2228 info->offset -= bytes;
2229 info->bytes += bytes;
2230
2231 if (update_stat)
2232 bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2233 else
2234 __bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2235
2236 if (!bitmap->bytes)
2237 free_bitmap(ctl, bitmap);
2238
2239 return true;
2240 }
2241
2242 /*
2243 * We prefer always to allocate from extent entries, both for clustered and
2244 * non-clustered allocation requests. So when attempting to add a new extent
2245 * entry, try to see if there's adjacent free space in bitmap entries, and if
2246 * there is, migrate that space from the bitmaps to the extent.
2247 * Like this we get better chances of satisfying space allocation requests
2248 * because we attempt to satisfy them based on a single cache entry, and never
2249 * on 2 or more entries - even if the entries represent a contiguous free space
2250 * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2251 * ends).
2252 */
2253 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2254 struct btrfs_free_space *info,
2255 bool update_stat)
2256 {
2257 /*
2258 * Only work with disconnected entries, as we can change their offset,
2259 * and must be extent entries.
2260 */
2261 ASSERT(!info->bitmap);
2262 ASSERT(RB_EMPTY_NODE(&info->offset_index));
2263
2264 if (ctl->total_bitmaps > 0) {
2265 bool stole_end;
2266 bool stole_front = false;
2267
2268 stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2269 if (ctl->total_bitmaps > 0)
2270 stole_front = steal_from_bitmap_to_front(ctl, info,
2271 update_stat);
2272
2273 if (stole_end || stole_front)
2274 try_merge_free_space(ctl, info, update_stat);
2275 }
2276 }
2277
2278 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
2279 u64 offset, u64 bytes)
2280 {
2281 struct btrfs_free_space *info;
2282 int ret = 0;
2283
2284 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2285 if (!info)
2286 return -ENOMEM;
2287
2288 info->offset = offset;
2289 info->bytes = bytes;
2290 RB_CLEAR_NODE(&info->offset_index);
2291
2292 spin_lock(&ctl->tree_lock);
2293
2294 if (try_merge_free_space(ctl, info, true))
2295 goto link;
2296
2297 /*
2298 * There was no extent directly to the left or right of this new
2299 * extent then we know we're going to have to allocate a new extent, so
2300 * before we do that see if we need to drop this into a bitmap
2301 */
2302 ret = insert_into_bitmap(ctl, info);
2303 if (ret < 0) {
2304 goto out;
2305 } else if (ret) {
2306 ret = 0;
2307 goto out;
2308 }
2309 link:
2310 /*
2311 * Only steal free space from adjacent bitmaps if we're sure we're not
2312 * going to add the new free space to existing bitmap entries - because
2313 * that would mean unnecessary work that would be reverted. Therefore
2314 * attempt to steal space from bitmaps if we're adding an extent entry.
2315 */
2316 steal_from_bitmap(ctl, info, true);
2317
2318 ret = link_free_space(ctl, info);
2319 if (ret)
2320 kmem_cache_free(btrfs_free_space_cachep, info);
2321 out:
2322 spin_unlock(&ctl->tree_lock);
2323
2324 if (ret) {
2325 printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2326 ASSERT(ret != -EEXIST);
2327 }
2328
2329 return ret;
2330 }
2331
2332 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2333 u64 offset, u64 bytes)
2334 {
2335 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2336 struct btrfs_free_space *info;
2337 int ret;
2338 bool re_search = false;
2339
2340 spin_lock(&ctl->tree_lock);
2341
2342 again:
2343 ret = 0;
2344 if (!bytes)
2345 goto out_lock;
2346
2347 info = tree_search_offset(ctl, offset, 0, 0);
2348 if (!info) {
2349 /*
2350 * oops didn't find an extent that matched the space we wanted
2351 * to remove, look for a bitmap instead
2352 */
2353 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2354 1, 0);
2355 if (!info) {
2356 /*
2357 * If we found a partial bit of our free space in a
2358 * bitmap but then couldn't find the other part this may
2359 * be a problem, so WARN about it.
2360 */
2361 WARN_ON(re_search);
2362 goto out_lock;
2363 }
2364 }
2365
2366 re_search = false;
2367 if (!info->bitmap) {
2368 unlink_free_space(ctl, info);
2369 if (offset == info->offset) {
2370 u64 to_free = min(bytes, info->bytes);
2371
2372 info->bytes -= to_free;
2373 info->offset += to_free;
2374 if (info->bytes) {
2375 ret = link_free_space(ctl, info);
2376 WARN_ON(ret);
2377 } else {
2378 kmem_cache_free(btrfs_free_space_cachep, info);
2379 }
2380
2381 offset += to_free;
2382 bytes -= to_free;
2383 goto again;
2384 } else {
2385 u64 old_end = info->bytes + info->offset;
2386
2387 info->bytes = offset - info->offset;
2388 ret = link_free_space(ctl, info);
2389 WARN_ON(ret);
2390 if (ret)
2391 goto out_lock;
2392
2393 /* Not enough bytes in this entry to satisfy us */
2394 if (old_end < offset + bytes) {
2395 bytes -= old_end - offset;
2396 offset = old_end;
2397 goto again;
2398 } else if (old_end == offset + bytes) {
2399 /* all done */
2400 goto out_lock;
2401 }
2402 spin_unlock(&ctl->tree_lock);
2403
2404 ret = btrfs_add_free_space(block_group, offset + bytes,
2405 old_end - (offset + bytes));
2406 WARN_ON(ret);
2407 goto out;
2408 }
2409 }
2410
2411 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2412 if (ret == -EAGAIN) {
2413 re_search = true;
2414 goto again;
2415 }
2416 out_lock:
2417 spin_unlock(&ctl->tree_lock);
2418 out:
2419 return ret;
2420 }
2421
2422 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2423 u64 bytes)
2424 {
2425 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2426 struct btrfs_free_space *info;
2427 struct rb_node *n;
2428 int count = 0;
2429
2430 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2431 info = rb_entry(n, struct btrfs_free_space, offset_index);
2432 if (info->bytes >= bytes && !block_group->ro)
2433 count++;
2434 btrfs_crit(block_group->fs_info,
2435 "entry offset %llu, bytes %llu, bitmap %s",
2436 info->offset, info->bytes,
2437 (info->bitmap) ? "yes" : "no");
2438 }
2439 btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2440 list_empty(&block_group->cluster_list) ? "no" : "yes");
2441 btrfs_info(block_group->fs_info,
2442 "%d blocks of free space at or bigger than bytes is", count);
2443 }
2444
2445 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2446 {
2447 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2448
2449 spin_lock_init(&ctl->tree_lock);
2450 ctl->unit = block_group->sectorsize;
2451 ctl->start = block_group->key.objectid;
2452 ctl->private = block_group;
2453 ctl->op = &free_space_op;
2454 INIT_LIST_HEAD(&ctl->trimming_ranges);
2455 mutex_init(&ctl->cache_writeout_mutex);
2456
2457 /*
2458 * we only want to have 32k of ram per block group for keeping
2459 * track of free space, and if we pass 1/2 of that we want to
2460 * start converting things over to using bitmaps
2461 */
2462 ctl->extents_thresh = ((1024 * 32) / 2) /
2463 sizeof(struct btrfs_free_space);
2464 }
2465
2466 /*
2467 * for a given cluster, put all of its extents back into the free
2468 * space cache. If the block group passed doesn't match the block group
2469 * pointed to by the cluster, someone else raced in and freed the
2470 * cluster already. In that case, we just return without changing anything
2471 */
2472 static int
2473 __btrfs_return_cluster_to_free_space(
2474 struct btrfs_block_group_cache *block_group,
2475 struct btrfs_free_cluster *cluster)
2476 {
2477 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2478 struct btrfs_free_space *entry;
2479 struct rb_node *node;
2480
2481 spin_lock(&cluster->lock);
2482 if (cluster->block_group != block_group)
2483 goto out;
2484
2485 cluster->block_group = NULL;
2486 cluster->window_start = 0;
2487 list_del_init(&cluster->block_group_list);
2488
2489 node = rb_first(&cluster->root);
2490 while (node) {
2491 bool bitmap;
2492
2493 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2494 node = rb_next(&entry->offset_index);
2495 rb_erase(&entry->offset_index, &cluster->root);
2496 RB_CLEAR_NODE(&entry->offset_index);
2497
2498 bitmap = (entry->bitmap != NULL);
2499 if (!bitmap) {
2500 try_merge_free_space(ctl, entry, false);
2501 steal_from_bitmap(ctl, entry, false);
2502 }
2503 tree_insert_offset(&ctl->free_space_offset,
2504 entry->offset, &entry->offset_index, bitmap);
2505 }
2506 cluster->root = RB_ROOT;
2507
2508 out:
2509 spin_unlock(&cluster->lock);
2510 btrfs_put_block_group(block_group);
2511 return 0;
2512 }
2513
2514 static void __btrfs_remove_free_space_cache_locked(
2515 struct btrfs_free_space_ctl *ctl)
2516 {
2517 struct btrfs_free_space *info;
2518 struct rb_node *node;
2519
2520 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2521 info = rb_entry(node, struct btrfs_free_space, offset_index);
2522 if (!info->bitmap) {
2523 unlink_free_space(ctl, info);
2524 kmem_cache_free(btrfs_free_space_cachep, info);
2525 } else {
2526 free_bitmap(ctl, info);
2527 }
2528
2529 cond_resched_lock(&ctl->tree_lock);
2530 }
2531 }
2532
2533 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2534 {
2535 spin_lock(&ctl->tree_lock);
2536 __btrfs_remove_free_space_cache_locked(ctl);
2537 spin_unlock(&ctl->tree_lock);
2538 }
2539
2540 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2541 {
2542 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2543 struct btrfs_free_cluster *cluster;
2544 struct list_head *head;
2545
2546 spin_lock(&ctl->tree_lock);
2547 while ((head = block_group->cluster_list.next) !=
2548 &block_group->cluster_list) {
2549 cluster = list_entry(head, struct btrfs_free_cluster,
2550 block_group_list);
2551
2552 WARN_ON(cluster->block_group != block_group);
2553 __btrfs_return_cluster_to_free_space(block_group, cluster);
2554
2555 cond_resched_lock(&ctl->tree_lock);
2556 }
2557 __btrfs_remove_free_space_cache_locked(ctl);
2558 spin_unlock(&ctl->tree_lock);
2559
2560 }
2561
2562 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2563 u64 offset, u64 bytes, u64 empty_size,
2564 u64 *max_extent_size)
2565 {
2566 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2567 struct btrfs_free_space *entry = NULL;
2568 u64 bytes_search = bytes + empty_size;
2569 u64 ret = 0;
2570 u64 align_gap = 0;
2571 u64 align_gap_len = 0;
2572
2573 spin_lock(&ctl->tree_lock);
2574 entry = find_free_space(ctl, &offset, &bytes_search,
2575 block_group->full_stripe_len, max_extent_size);
2576 if (!entry)
2577 goto out;
2578
2579 ret = offset;
2580 if (entry->bitmap) {
2581 bitmap_clear_bits(ctl, entry, offset, bytes);
2582 if (!entry->bytes)
2583 free_bitmap(ctl, entry);
2584 } else {
2585 unlink_free_space(ctl, entry);
2586 align_gap_len = offset - entry->offset;
2587 align_gap = entry->offset;
2588
2589 entry->offset = offset + bytes;
2590 WARN_ON(entry->bytes < bytes + align_gap_len);
2591
2592 entry->bytes -= bytes + align_gap_len;
2593 if (!entry->bytes)
2594 kmem_cache_free(btrfs_free_space_cachep, entry);
2595 else
2596 link_free_space(ctl, entry);
2597 }
2598 out:
2599 spin_unlock(&ctl->tree_lock);
2600
2601 if (align_gap_len)
2602 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2603 return ret;
2604 }
2605
2606 /*
2607 * given a cluster, put all of its extents back into the free space
2608 * cache. If a block group is passed, this function will only free
2609 * a cluster that belongs to the passed block group.
2610 *
2611 * Otherwise, it'll get a reference on the block group pointed to by the
2612 * cluster and remove the cluster from it.
2613 */
2614 int btrfs_return_cluster_to_free_space(
2615 struct btrfs_block_group_cache *block_group,
2616 struct btrfs_free_cluster *cluster)
2617 {
2618 struct btrfs_free_space_ctl *ctl;
2619 int ret;
2620
2621 /* first, get a safe pointer to the block group */
2622 spin_lock(&cluster->lock);
2623 if (!block_group) {
2624 block_group = cluster->block_group;
2625 if (!block_group) {
2626 spin_unlock(&cluster->lock);
2627 return 0;
2628 }
2629 } else if (cluster->block_group != block_group) {
2630 /* someone else has already freed it don't redo their work */
2631 spin_unlock(&cluster->lock);
2632 return 0;
2633 }
2634 atomic_inc(&block_group->count);
2635 spin_unlock(&cluster->lock);
2636
2637 ctl = block_group->free_space_ctl;
2638
2639 /* now return any extents the cluster had on it */
2640 spin_lock(&ctl->tree_lock);
2641 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2642 spin_unlock(&ctl->tree_lock);
2643
2644 /* finally drop our ref */
2645 btrfs_put_block_group(block_group);
2646 return ret;
2647 }
2648
2649 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2650 struct btrfs_free_cluster *cluster,
2651 struct btrfs_free_space *entry,
2652 u64 bytes, u64 min_start,
2653 u64 *max_extent_size)
2654 {
2655 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2656 int err;
2657 u64 search_start = cluster->window_start;
2658 u64 search_bytes = bytes;
2659 u64 ret = 0;
2660
2661 search_start = min_start;
2662 search_bytes = bytes;
2663
2664 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2665 if (err) {
2666 if (search_bytes > *max_extent_size)
2667 *max_extent_size = search_bytes;
2668 return 0;
2669 }
2670
2671 ret = search_start;
2672 __bitmap_clear_bits(ctl, entry, ret, bytes);
2673
2674 return ret;
2675 }
2676
2677 /*
2678 * given a cluster, try to allocate 'bytes' from it, returns 0
2679 * if it couldn't find anything suitably large, or a logical disk offset
2680 * if things worked out
2681 */
2682 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2683 struct btrfs_free_cluster *cluster, u64 bytes,
2684 u64 min_start, u64 *max_extent_size)
2685 {
2686 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2687 struct btrfs_free_space *entry = NULL;
2688 struct rb_node *node;
2689 u64 ret = 0;
2690
2691 spin_lock(&cluster->lock);
2692 if (bytes > cluster->max_size)
2693 goto out;
2694
2695 if (cluster->block_group != block_group)
2696 goto out;
2697
2698 node = rb_first(&cluster->root);
2699 if (!node)
2700 goto out;
2701
2702 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2703 while (1) {
2704 if (entry->bytes < bytes && entry->bytes > *max_extent_size)
2705 *max_extent_size = entry->bytes;
2706
2707 if (entry->bytes < bytes ||
2708 (!entry->bitmap && entry->offset < min_start)) {
2709 node = rb_next(&entry->offset_index);
2710 if (!node)
2711 break;
2712 entry = rb_entry(node, struct btrfs_free_space,
2713 offset_index);
2714 continue;
2715 }
2716
2717 if (entry->bitmap) {
2718 ret = btrfs_alloc_from_bitmap(block_group,
2719 cluster, entry, bytes,
2720 cluster->window_start,
2721 max_extent_size);
2722 if (ret == 0) {
2723 node = rb_next(&entry->offset_index);
2724 if (!node)
2725 break;
2726 entry = rb_entry(node, struct btrfs_free_space,
2727 offset_index);
2728 continue;
2729 }
2730 cluster->window_start += bytes;
2731 } else {
2732 ret = entry->offset;
2733
2734 entry->offset += bytes;
2735 entry->bytes -= bytes;
2736 }
2737
2738 if (entry->bytes == 0)
2739 rb_erase(&entry->offset_index, &cluster->root);
2740 break;
2741 }
2742 out:
2743 spin_unlock(&cluster->lock);
2744
2745 if (!ret)
2746 return 0;
2747
2748 spin_lock(&ctl->tree_lock);
2749
2750 ctl->free_space -= bytes;
2751 if (entry->bytes == 0) {
2752 ctl->free_extents--;
2753 if (entry->bitmap) {
2754 kfree(entry->bitmap);
2755 ctl->total_bitmaps--;
2756 ctl->op->recalc_thresholds(ctl);
2757 }
2758 kmem_cache_free(btrfs_free_space_cachep, entry);
2759 }
2760
2761 spin_unlock(&ctl->tree_lock);
2762
2763 return ret;
2764 }
2765
2766 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2767 struct btrfs_free_space *entry,
2768 struct btrfs_free_cluster *cluster,
2769 u64 offset, u64 bytes,
2770 u64 cont1_bytes, u64 min_bytes)
2771 {
2772 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2773 unsigned long next_zero;
2774 unsigned long i;
2775 unsigned long want_bits;
2776 unsigned long min_bits;
2777 unsigned long found_bits;
2778 unsigned long start = 0;
2779 unsigned long total_found = 0;
2780 int ret;
2781
2782 i = offset_to_bit(entry->offset, ctl->unit,
2783 max_t(u64, offset, entry->offset));
2784 want_bits = bytes_to_bits(bytes, ctl->unit);
2785 min_bits = bytes_to_bits(min_bytes, ctl->unit);
2786
2787 again:
2788 found_bits = 0;
2789 for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2790 next_zero = find_next_zero_bit(entry->bitmap,
2791 BITS_PER_BITMAP, i);
2792 if (next_zero - i >= min_bits) {
2793 found_bits = next_zero - i;
2794 break;
2795 }
2796 i = next_zero;
2797 }
2798
2799 if (!found_bits)
2800 return -ENOSPC;
2801
2802 if (!total_found) {
2803 start = i;
2804 cluster->max_size = 0;
2805 }
2806
2807 total_found += found_bits;
2808
2809 if (cluster->max_size < found_bits * ctl->unit)
2810 cluster->max_size = found_bits * ctl->unit;
2811
2812 if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2813 i = next_zero + 1;
2814 goto again;
2815 }
2816
2817 cluster->window_start = start * ctl->unit + entry->offset;
2818 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2819 ret = tree_insert_offset(&cluster->root, entry->offset,
2820 &entry->offset_index, 1);
2821 ASSERT(!ret); /* -EEXIST; Logic error */
2822
2823 trace_btrfs_setup_cluster(block_group, cluster,
2824 total_found * ctl->unit, 1);
2825 return 0;
2826 }
2827
2828 /*
2829 * This searches the block group for just extents to fill the cluster with.
2830 * Try to find a cluster with at least bytes total bytes, at least one
2831 * extent of cont1_bytes, and other clusters of at least min_bytes.
2832 */
2833 static noinline int
2834 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2835 struct btrfs_free_cluster *cluster,
2836 struct list_head *bitmaps, u64 offset, u64 bytes,
2837 u64 cont1_bytes, u64 min_bytes)
2838 {
2839 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2840 struct btrfs_free_space *first = NULL;
2841 struct btrfs_free_space *entry = NULL;
2842 struct btrfs_free_space *last;
2843 struct rb_node *node;
2844 u64 window_free;
2845 u64 max_extent;
2846 u64 total_size = 0;
2847
2848 entry = tree_search_offset(ctl, offset, 0, 1);
2849 if (!entry)
2850 return -ENOSPC;
2851
2852 /*
2853 * We don't want bitmaps, so just move along until we find a normal
2854 * extent entry.
2855 */
2856 while (entry->bitmap || entry->bytes < min_bytes) {
2857 if (entry->bitmap && list_empty(&entry->list))
2858 list_add_tail(&entry->list, bitmaps);
2859 node = rb_next(&entry->offset_index);
2860 if (!node)
2861 return -ENOSPC;
2862 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2863 }
2864
2865 window_free = entry->bytes;
2866 max_extent = entry->bytes;
2867 first = entry;
2868 last = entry;
2869
2870 for (node = rb_next(&entry->offset_index); node;
2871 node = rb_next(&entry->offset_index)) {
2872 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2873
2874 if (entry->bitmap) {
2875 if (list_empty(&entry->list))
2876 list_add_tail(&entry->list, bitmaps);
2877 continue;
2878 }
2879
2880 if (entry->bytes < min_bytes)
2881 continue;
2882
2883 last = entry;
2884 window_free += entry->bytes;
2885 if (entry->bytes > max_extent)
2886 max_extent = entry->bytes;
2887 }
2888
2889 if (window_free < bytes || max_extent < cont1_bytes)
2890 return -ENOSPC;
2891
2892 cluster->window_start = first->offset;
2893
2894 node = &first->offset_index;
2895
2896 /*
2897 * now we've found our entries, pull them out of the free space
2898 * cache and put them into the cluster rbtree
2899 */
2900 do {
2901 int ret;
2902
2903 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2904 node = rb_next(&entry->offset_index);
2905 if (entry->bitmap || entry->bytes < min_bytes)
2906 continue;
2907
2908 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2909 ret = tree_insert_offset(&cluster->root, entry->offset,
2910 &entry->offset_index, 0);
2911 total_size += entry->bytes;
2912 ASSERT(!ret); /* -EEXIST; Logic error */
2913 } while (node && entry != last);
2914
2915 cluster->max_size = max_extent;
2916 trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2917 return 0;
2918 }
2919
2920 /*
2921 * This specifically looks for bitmaps that may work in the cluster, we assume
2922 * that we have already failed to find extents that will work.
2923 */
2924 static noinline int
2925 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2926 struct btrfs_free_cluster *cluster,
2927 struct list_head *bitmaps, u64 offset, u64 bytes,
2928 u64 cont1_bytes, u64 min_bytes)
2929 {
2930 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2931 struct btrfs_free_space *entry;
2932 int ret = -ENOSPC;
2933 u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2934
2935 if (ctl->total_bitmaps == 0)
2936 return -ENOSPC;
2937
2938 /*
2939 * The bitmap that covers offset won't be in the list unless offset
2940 * is just its start offset.
2941 */
2942 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2943 if (entry->offset != bitmap_offset) {
2944 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2945 if (entry && list_empty(&entry->list))
2946 list_add(&entry->list, bitmaps);
2947 }
2948
2949 list_for_each_entry(entry, bitmaps, list) {
2950 if (entry->bytes < bytes)
2951 continue;
2952 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2953 bytes, cont1_bytes, min_bytes);
2954 if (!ret)
2955 return 0;
2956 }
2957
2958 /*
2959 * The bitmaps list has all the bitmaps that record free space
2960 * starting after offset, so no more search is required.
2961 */
2962 return -ENOSPC;
2963 }
2964
2965 /*
2966 * here we try to find a cluster of blocks in a block group. The goal
2967 * is to find at least bytes+empty_size.
2968 * We might not find them all in one contiguous area.
2969 *
2970 * returns zero and sets up cluster if things worked out, otherwise
2971 * it returns -enospc
2972 */
2973 int btrfs_find_space_cluster(struct btrfs_root *root,
2974 struct btrfs_block_group_cache *block_group,
2975 struct btrfs_free_cluster *cluster,
2976 u64 offset, u64 bytes, u64 empty_size)
2977 {
2978 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2979 struct btrfs_free_space *entry, *tmp;
2980 LIST_HEAD(bitmaps);
2981 u64 min_bytes;
2982 u64 cont1_bytes;
2983 int ret;
2984
2985 /*
2986 * Choose the minimum extent size we'll require for this
2987 * cluster. For SSD_SPREAD, don't allow any fragmentation.
2988 * For metadata, allow allocates with smaller extents. For
2989 * data, keep it dense.
2990 */
2991 if (btrfs_test_opt(root, SSD_SPREAD)) {
2992 cont1_bytes = min_bytes = bytes + empty_size;
2993 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2994 cont1_bytes = bytes;
2995 min_bytes = block_group->sectorsize;
2996 } else {
2997 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2998 min_bytes = block_group->sectorsize;
2999 }
3000
3001 spin_lock(&ctl->tree_lock);
3002
3003 /*
3004 * If we know we don't have enough space to make a cluster don't even
3005 * bother doing all the work to try and find one.
3006 */
3007 if (ctl->free_space < bytes) {
3008 spin_unlock(&ctl->tree_lock);
3009 return -ENOSPC;
3010 }
3011
3012 spin_lock(&cluster->lock);
3013
3014 /* someone already found a cluster, hooray */
3015 if (cluster->block_group) {
3016 ret = 0;
3017 goto out;
3018 }
3019
3020 trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3021 min_bytes);
3022
3023 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3024 bytes + empty_size,
3025 cont1_bytes, min_bytes);
3026 if (ret)
3027 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3028 offset, bytes + empty_size,
3029 cont1_bytes, min_bytes);
3030
3031 /* Clear our temporary list */
3032 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3033 list_del_init(&entry->list);
3034
3035 if (!ret) {
3036 atomic_inc(&block_group->count);
3037 list_add_tail(&cluster->block_group_list,
3038 &block_group->cluster_list);
3039 cluster->block_group = block_group;
3040 } else {
3041 trace_btrfs_failed_cluster_setup(block_group);
3042 }
3043 out:
3044 spin_unlock(&cluster->lock);
3045 spin_unlock(&ctl->tree_lock);
3046
3047 return ret;
3048 }
3049
3050 /*
3051 * simple code to zero out a cluster
3052 */
3053 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3054 {
3055 spin_lock_init(&cluster->lock);
3056 spin_lock_init(&cluster->refill_lock);
3057 cluster->root = RB_ROOT;
3058 cluster->max_size = 0;
3059 INIT_LIST_HEAD(&cluster->block_group_list);
3060 cluster->block_group = NULL;
3061 }
3062
3063 static int do_trimming(struct btrfs_block_group_cache *block_group,
3064 u64 *total_trimmed, u64 start, u64 bytes,
3065 u64 reserved_start, u64 reserved_bytes,
3066 struct btrfs_trim_range *trim_entry)
3067 {
3068 struct btrfs_space_info *space_info = block_group->space_info;
3069 struct btrfs_fs_info *fs_info = block_group->fs_info;
3070 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3071 int ret;
3072 int update = 0;
3073 u64 trimmed = 0;
3074
3075 spin_lock(&space_info->lock);
3076 spin_lock(&block_group->lock);
3077 if (!block_group->ro) {
3078 block_group->reserved += reserved_bytes;
3079 space_info->bytes_reserved += reserved_bytes;
3080 update = 1;
3081 }
3082 spin_unlock(&block_group->lock);
3083 spin_unlock(&space_info->lock);
3084
3085 ret = btrfs_discard_extent(fs_info->extent_root,
3086 start, bytes, &trimmed);
3087 if (!ret)
3088 *total_trimmed += trimmed;
3089
3090 mutex_lock(&ctl->cache_writeout_mutex);
3091 btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
3092 list_del(&trim_entry->list);
3093 mutex_unlock(&ctl->cache_writeout_mutex);
3094
3095 if (update) {
3096 spin_lock(&space_info->lock);
3097 spin_lock(&block_group->lock);
3098 if (block_group->ro)
3099 space_info->bytes_readonly += reserved_bytes;
3100 block_group->reserved -= reserved_bytes;
3101 space_info->bytes_reserved -= reserved_bytes;
3102 spin_unlock(&space_info->lock);
3103 spin_unlock(&block_group->lock);
3104 }
3105
3106 return ret;
3107 }
3108
3109 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
3110 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3111 {
3112 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3113 struct btrfs_free_space *entry;
3114 struct rb_node *node;
3115 int ret = 0;
3116 u64 extent_start;
3117 u64 extent_bytes;
3118 u64 bytes;
3119
3120 while (start < end) {
3121 struct btrfs_trim_range trim_entry;
3122
3123 mutex_lock(&ctl->cache_writeout_mutex);
3124 spin_lock(&ctl->tree_lock);
3125
3126 if (ctl->free_space < minlen) {
3127 spin_unlock(&ctl->tree_lock);
3128 mutex_unlock(&ctl->cache_writeout_mutex);
3129 break;
3130 }
3131
3132 entry = tree_search_offset(ctl, start, 0, 1);
3133 if (!entry) {
3134 spin_unlock(&ctl->tree_lock);
3135 mutex_unlock(&ctl->cache_writeout_mutex);
3136 break;
3137 }
3138
3139 /* skip bitmaps */
3140 while (entry->bitmap) {
3141 node = rb_next(&entry->offset_index);
3142 if (!node) {
3143 spin_unlock(&ctl->tree_lock);
3144 mutex_unlock(&ctl->cache_writeout_mutex);
3145 goto out;
3146 }
3147 entry = rb_entry(node, struct btrfs_free_space,
3148 offset_index);
3149 }
3150
3151 if (entry->offset >= end) {
3152 spin_unlock(&ctl->tree_lock);
3153 mutex_unlock(&ctl->cache_writeout_mutex);
3154 break;
3155 }
3156
3157 extent_start = entry->offset;
3158 extent_bytes = entry->bytes;
3159 start = max(start, extent_start);
3160 bytes = min(extent_start + extent_bytes, end) - start;
3161 if (bytes < minlen) {
3162 spin_unlock(&ctl->tree_lock);
3163 mutex_unlock(&ctl->cache_writeout_mutex);
3164 goto next;
3165 }
3166
3167 unlink_free_space(ctl, entry);
3168 kmem_cache_free(btrfs_free_space_cachep, entry);
3169
3170 spin_unlock(&ctl->tree_lock);
3171 trim_entry.start = extent_start;
3172 trim_entry.bytes = extent_bytes;
3173 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3174 mutex_unlock(&ctl->cache_writeout_mutex);
3175
3176 ret = do_trimming(block_group, total_trimmed, start, bytes,
3177 extent_start, extent_bytes, &trim_entry);
3178 if (ret)
3179 break;
3180 next:
3181 start += bytes;
3182
3183 if (fatal_signal_pending(current)) {
3184 ret = -ERESTARTSYS;
3185 break;
3186 }
3187
3188 cond_resched();
3189 }
3190 out:
3191 return ret;
3192 }
3193
3194 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
3195 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3196 {
3197 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3198 struct btrfs_free_space *entry;
3199 int ret = 0;
3200 int ret2;
3201 u64 bytes;
3202 u64 offset = offset_to_bitmap(ctl, start);
3203
3204 while (offset < end) {
3205 bool next_bitmap = false;
3206 struct btrfs_trim_range trim_entry;
3207
3208 mutex_lock(&ctl->cache_writeout_mutex);
3209 spin_lock(&ctl->tree_lock);
3210
3211 if (ctl->free_space < minlen) {
3212 spin_unlock(&ctl->tree_lock);
3213 mutex_unlock(&ctl->cache_writeout_mutex);
3214 break;
3215 }
3216
3217 entry = tree_search_offset(ctl, offset, 1, 0);
3218 if (!entry) {
3219 spin_unlock(&ctl->tree_lock);
3220 mutex_unlock(&ctl->cache_writeout_mutex);
3221 next_bitmap = true;
3222 goto next;
3223 }
3224
3225 bytes = minlen;
3226 ret2 = search_bitmap(ctl, entry, &start, &bytes);
3227 if (ret2 || start >= end) {
3228 spin_unlock(&ctl->tree_lock);
3229 mutex_unlock(&ctl->cache_writeout_mutex);
3230 next_bitmap = true;
3231 goto next;
3232 }
3233
3234 bytes = min(bytes, end - start);
3235 if (bytes < minlen) {
3236 spin_unlock(&ctl->tree_lock);
3237 mutex_unlock(&ctl->cache_writeout_mutex);
3238 goto next;
3239 }
3240
3241 bitmap_clear_bits(ctl, entry, start, bytes);
3242 if (entry->bytes == 0)
3243 free_bitmap(ctl, entry);
3244
3245 spin_unlock(&ctl->tree_lock);
3246 trim_entry.start = start;
3247 trim_entry.bytes = bytes;
3248 list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3249 mutex_unlock(&ctl->cache_writeout_mutex);
3250
3251 ret = do_trimming(block_group, total_trimmed, start, bytes,
3252 start, bytes, &trim_entry);
3253 if (ret)
3254 break;
3255 next:
3256 if (next_bitmap) {
3257 offset += BITS_PER_BITMAP * ctl->unit;
3258 } else {
3259 start += bytes;
3260 if (start >= offset + BITS_PER_BITMAP * ctl->unit)
3261 offset += BITS_PER_BITMAP * ctl->unit;
3262 }
3263
3264 if (fatal_signal_pending(current)) {
3265 ret = -ERESTARTSYS;
3266 break;
3267 }
3268
3269 cond_resched();
3270 }
3271
3272 return ret;
3273 }
3274
3275 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
3276 u64 *trimmed, u64 start, u64 end, u64 minlen)
3277 {
3278 int ret;
3279
3280 *trimmed = 0;
3281
3282 spin_lock(&block_group->lock);
3283 if (block_group->removed) {
3284 spin_unlock(&block_group->lock);
3285 return 0;
3286 }
3287 atomic_inc(&block_group->trimming);
3288 spin_unlock(&block_group->lock);
3289
3290 ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
3291 if (ret)
3292 goto out;
3293
3294 ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
3295 out:
3296 spin_lock(&block_group->lock);
3297 if (atomic_dec_and_test(&block_group->trimming) &&
3298 block_group->removed) {
3299 struct extent_map_tree *em_tree;
3300 struct extent_map *em;
3301
3302 spin_unlock(&block_group->lock);
3303
3304 lock_chunks(block_group->fs_info->chunk_root);
3305 em_tree = &block_group->fs_info->mapping_tree.map_tree;
3306 write_lock(&em_tree->lock);
3307 em = lookup_extent_mapping(em_tree, block_group->key.objectid,
3308 1);
3309 BUG_ON(!em); /* logic error, can't happen */
3310 /*
3311 * remove_extent_mapping() will delete us from the pinned_chunks
3312 * list, which is protected by the chunk mutex.
3313 */
3314 remove_extent_mapping(em_tree, em);
3315 write_unlock(&em_tree->lock);
3316 unlock_chunks(block_group->fs_info->chunk_root);
3317
3318 /* once for us and once for the tree */
3319 free_extent_map(em);
3320 free_extent_map(em);
3321
3322 /*
3323 * We've left one free space entry and other tasks trimming
3324 * this block group have left 1 entry each one. Free them.
3325 */
3326 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3327 } else {
3328 spin_unlock(&block_group->lock);
3329 }
3330
3331 return ret;
3332 }
3333
3334 /*
3335 * Find the left-most item in the cache tree, and then return the
3336 * smallest inode number in the item.
3337 *
3338 * Note: the returned inode number may not be the smallest one in
3339 * the tree, if the left-most item is a bitmap.
3340 */
3341 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
3342 {
3343 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
3344 struct btrfs_free_space *entry = NULL;
3345 u64 ino = 0;
3346
3347 spin_lock(&ctl->tree_lock);
3348
3349 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
3350 goto out;
3351
3352 entry = rb_entry(rb_first(&ctl->free_space_offset),
3353 struct btrfs_free_space, offset_index);
3354
3355 if (!entry->bitmap) {
3356 ino = entry->offset;
3357
3358 unlink_free_space(ctl, entry);
3359 entry->offset++;
3360 entry->bytes--;
3361 if (!entry->bytes)
3362 kmem_cache_free(btrfs_free_space_cachep, entry);
3363 else
3364 link_free_space(ctl, entry);
3365 } else {
3366 u64 offset = 0;
3367 u64 count = 1;
3368 int ret;
3369
3370 ret = search_bitmap(ctl, entry, &offset, &count);
3371 /* Logic error; Should be empty if it can't find anything */
3372 ASSERT(!ret);
3373
3374 ino = offset;
3375 bitmap_clear_bits(ctl, entry, offset, 1);
3376 if (entry->bytes == 0)
3377 free_bitmap(ctl, entry);
3378 }
3379 out:
3380 spin_unlock(&ctl->tree_lock);
3381
3382 return ino;
3383 }
3384
3385 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3386 struct btrfs_path *path)
3387 {
3388 struct inode *inode = NULL;
3389
3390 spin_lock(&root->ino_cache_lock);
3391 if (root->ino_cache_inode)
3392 inode = igrab(root->ino_cache_inode);
3393 spin_unlock(&root->ino_cache_lock);
3394 if (inode)
3395 return inode;
3396
3397 inode = __lookup_free_space_inode(root, path, 0);
3398 if (IS_ERR(inode))
3399 return inode;
3400
3401 spin_lock(&root->ino_cache_lock);
3402 if (!btrfs_fs_closing(root->fs_info))
3403 root->ino_cache_inode = igrab(inode);
3404 spin_unlock(&root->ino_cache_lock);
3405
3406 return inode;
3407 }
3408
3409 int create_free_ino_inode(struct btrfs_root *root,
3410 struct btrfs_trans_handle *trans,
3411 struct btrfs_path *path)
3412 {
3413 return __create_free_space_inode(root, trans, path,
3414 BTRFS_FREE_INO_OBJECTID, 0);
3415 }
3416
3417 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3418 {
3419 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3420 struct btrfs_path *path;
3421 struct inode *inode;
3422 int ret = 0;
3423 u64 root_gen = btrfs_root_generation(&root->root_item);
3424
3425 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3426 return 0;
3427
3428 /*
3429 * If we're unmounting then just return, since this does a search on the
3430 * normal root and not the commit root and we could deadlock.
3431 */
3432 if (btrfs_fs_closing(fs_info))
3433 return 0;
3434
3435 path = btrfs_alloc_path();
3436 if (!path)
3437 return 0;
3438
3439 inode = lookup_free_ino_inode(root, path);
3440 if (IS_ERR(inode))
3441 goto out;
3442
3443 if (root_gen != BTRFS_I(inode)->generation)
3444 goto out_put;
3445
3446 ret = __load_free_space_cache(root, inode, ctl, path, 0);
3447
3448 if (ret < 0)
3449 btrfs_err(fs_info,
3450 "failed to load free ino cache for root %llu",
3451 root->root_key.objectid);
3452 out_put:
3453 iput(inode);
3454 out:
3455 btrfs_free_path(path);
3456 return ret;
3457 }
3458
3459 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3460 struct btrfs_trans_handle *trans,
3461 struct btrfs_path *path,
3462 struct inode *inode)
3463 {
3464 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3465 int ret;
3466 struct btrfs_io_ctl io_ctl;
3467 bool release_metadata = true;
3468
3469 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3470 return 0;
3471
3472 memset(&io_ctl, 0, sizeof(io_ctl));
3473 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl,
3474 trans, path, 0);
3475 if (!ret) {
3476 /*
3477 * At this point writepages() didn't error out, so our metadata
3478 * reservation is released when the writeback finishes, at
3479 * inode.c:btrfs_finish_ordered_io(), regardless of it finishing
3480 * with or without an error.
3481 */
3482 release_metadata = false;
3483 ret = btrfs_wait_cache_io(root, trans, NULL, &io_ctl, path, 0);
3484 }
3485
3486 if (ret) {
3487 if (release_metadata)
3488 btrfs_delalloc_release_metadata(inode, inode->i_size);
3489 #ifdef DEBUG
3490 btrfs_err(root->fs_info,
3491 "failed to write free ino cache for root %llu",
3492 root->root_key.objectid);
3493 #endif
3494 }
3495
3496 return ret;
3497 }
3498
3499 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3500 /*
3501 * Use this if you need to make a bitmap or extent entry specifically, it
3502 * doesn't do any of the merging that add_free_space does, this acts a lot like
3503 * how the free space cache loading stuff works, so you can get really weird
3504 * configurations.
3505 */
3506 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3507 u64 offset, u64 bytes, bool bitmap)
3508 {
3509 struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3510 struct btrfs_free_space *info = NULL, *bitmap_info;
3511 void *map = NULL;
3512 u64 bytes_added;
3513 int ret;
3514
3515 again:
3516 if (!info) {
3517 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3518 if (!info)
3519 return -ENOMEM;
3520 }
3521
3522 if (!bitmap) {
3523 spin_lock(&ctl->tree_lock);
3524 info->offset = offset;
3525 info->bytes = bytes;
3526 ret = link_free_space(ctl, info);
3527 spin_unlock(&ctl->tree_lock);
3528 if (ret)
3529 kmem_cache_free(btrfs_free_space_cachep, info);
3530 return ret;
3531 }
3532
3533 if (!map) {
3534 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3535 if (!map) {
3536 kmem_cache_free(btrfs_free_space_cachep, info);
3537 return -ENOMEM;
3538 }
3539 }
3540
3541 spin_lock(&ctl->tree_lock);
3542 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3543 1, 0);
3544 if (!bitmap_info) {
3545 info->bitmap = map;
3546 map = NULL;
3547 add_new_bitmap(ctl, info, offset);
3548 bitmap_info = info;
3549 info = NULL;
3550 }
3551
3552 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3553 bytes -= bytes_added;
3554 offset += bytes_added;
3555 spin_unlock(&ctl->tree_lock);
3556
3557 if (bytes)
3558 goto again;
3559
3560 if (info)
3561 kmem_cache_free(btrfs_free_space_cachep, info);
3562 if (map)
3563 kfree(map);
3564 return 0;
3565 }
3566
3567 /*
3568 * Checks to see if the given range is in the free space cache. This is really
3569 * just used to check the absence of space, so if there is free space in the
3570 * range at all we will return 1.
3571 */
3572 int test_check_exists(struct btrfs_block_group_cache *cache,
3573 u64 offset, u64 bytes)
3574 {
3575 struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3576 struct btrfs_free_space *info;
3577 int ret = 0;
3578
3579 spin_lock(&ctl->tree_lock);
3580 info = tree_search_offset(ctl, offset, 0, 0);
3581 if (!info) {
3582 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3583 1, 0);
3584 if (!info)
3585 goto out;
3586 }
3587
3588 have_info:
3589 if (info->bitmap) {
3590 u64 bit_off, bit_bytes;
3591 struct rb_node *n;
3592 struct btrfs_free_space *tmp;
3593
3594 bit_off = offset;
3595 bit_bytes = ctl->unit;
3596 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3597 if (!ret) {
3598 if (bit_off == offset) {
3599 ret = 1;
3600 goto out;
3601 } else if (bit_off > offset &&
3602 offset + bytes > bit_off) {
3603 ret = 1;
3604 goto out;
3605 }
3606 }
3607
3608 n = rb_prev(&info->offset_index);
3609 while (n) {
3610 tmp = rb_entry(n, struct btrfs_free_space,
3611 offset_index);
3612 if (tmp->offset + tmp->bytes < offset)
3613 break;
3614 if (offset + bytes < tmp->offset) {
3615 n = rb_prev(&info->offset_index);
3616 continue;
3617 }
3618 info = tmp;
3619 goto have_info;
3620 }
3621
3622 n = rb_next(&info->offset_index);
3623 while (n) {
3624 tmp = rb_entry(n, struct btrfs_free_space,
3625 offset_index);
3626 if (offset + bytes < tmp->offset)
3627 break;
3628 if (tmp->offset + tmp->bytes < offset) {
3629 n = rb_next(&info->offset_index);
3630 continue;
3631 }
3632 info = tmp;
3633 goto have_info;
3634 }
3635
3636 ret = 0;
3637 goto out;
3638 }
3639
3640 if (info->offset == offset) {
3641 ret = 1;
3642 goto out;
3643 }
3644
3645 if (offset > info->offset && offset < info->offset + info->bytes)
3646 ret = 1;
3647 out:
3648 spin_unlock(&ctl->tree_lock);
3649 return ret;
3650 }
3651 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
Linux with added FPC-III support